GDPS: The Enterprise Continuous Availability / Disaster Recovery Solution

Transcription

1 Executive Summary March 2009 GDPS: The Enterprise Continuous Availability / Disaster Recovery Solution Noshir Dhondy dhondy@us.ibm.com David Raften raften@us.ibm.com 1

2 Table of Contents Introduction...2 Lessons learned about IT survival...6 What is a GDPS?...7 Need for Data Consistency...8 GDPS Systems...9 Need for Automation...10 GDPS/PPRC...11 Planned Reconfiguration support...12 Unplanned Reconfiguration support...13 Near Continuous Availability of data with HyperSwap...13 Benchmark measurements using HyperSwap for Planned Reconfiguration...13 Benchmark measurements using HyperSwap for Unplanned Reconfiguration...14 GDPS/PPRC HyperSwap Manager...15 Near continuous availability of data within a single site...16 Near continuous availability of data/disaster Recovery solution at metropolitan distances...16 GDPS/XRC...17 Planned Reconfiguration support...18 GDPS/Global Mirror...19 Three Site Solutions...20 Functions common to multiple GDPS solutions...21 Peer-to-Peer Virtual Tape Server (PtP VTS) support...21 FlashCopy support...21 Support for Heterogeneous Environments...21 Management of IBM System z Operating Systems...21 GDPS/PPRC, GDPS/PPRC HM, and GDPS/GM Open LUN Management...22 GDPS/PPRC Multiplatform Resiliency for System z...22 Distributed Cluster Manager...23 Recent Enhancements in GDPS V IBM Global Technology Services (GTS) Offerings...25 Technical Consulting Workshop (TCW)...25 IBM Implementation Services for Geographically Dispersed Open Clusters (GDOC)...25 IBM Installation Services for GDPS...26 GDPS integrated with GDOC...26 Prerequisites...27 GDPS/PPRC at work in a real disaster...27 Summary...28 Additional Information

3 Introduction How would a shutdown of your z/os system affect your business? Do you put off system maintenance and upgrades to help minimize system downtime? Are your business-critical processing and data protected from a site disaster? A 2006 survey conducted by the Robert Frances Group, Figure 1, Cost of Outage/hour, shows the participating companies' responses to the hourly impact of an outage. Cost of Downtime by Industry Industry/Sector Revenue/Hour Financial $8,213,470 Telecommunications $4,611,604 Information Technology $3,316,058 Insurance $2,582,382 Pharmaceuticals $2,058,710 Energy $1,468,798 Transportation $1,463,128 Banking $1,145,129 Chemicals $1,071,404 Consumer Products $989,795 Source: Robert Frances Group 2006, Picking up the value of PKI: Leveraging z/os for Improving Manageability, Reliability, and Total Cost of Ownership of PKI and Digital Certificates. Figure 1: Cost of Outage/hour All enterprises have become much more dependent on Information Technology (IT) since the survey results were compiled. As a result, the average hourly cost of an outage could be significantly higher today than what is shown in Figure 1. It has been observed that many companies have business continuance plans developed on the premise that back office and manual processes will keep the business running until computer systems are available. Characteristics of these recovery models may allow critical applications to recover within 24 to 48 hours, with data loss potentially exceeding 24 hours, and full business recovery taking days or weeks. As companies transform their business to compete in the e-marketplace, business continuity strategies and availability requirements should be reevaluated to determine if they are based on today s business objectives. 2

4 At what point is the survival of your company at risk? 72 hrs 40.0% < 1 hr 4.0% 1 hr 3.0% 4 hrs 9.0% 8 hrs 8.0% 24 hrs 15.0% 48 hrs 21.0% < 1 hr 1 hr 4 hrs 8 hrs 24 hrs 48 hrs 72 hrs Figure 2: Survival of company at risk (c) Eagle Rock Alliance, LTD. All Rights Reserved Source: 2001 Survey by Eagle Rock Alliance ( In a different survey, respondents were also asked at what point is the survival of their company at risk. The results are summarized in Figure 2, Survival of company at risk. Just as explained above for the cost of outages, it may also be expected that in today s e-marketplace, a larger percentage of businesses may not survive an outage of even a limited duration of 4 to 8 hours. Two important objectives for survival are systems designed to provide continuous availability and near transparent disaster recovery (D/R). Systems that are designed to deliver continuous availability combine the characteristics of high availability and near continuous operations to deliver high levels of service targeted at 24x7. High availability is an attribute of a system that provides service at agreed upon levels and can mask unplanned outages from end users. Near continuous operation, on the other hand, is the attribute of a system designed to continuously operate and mask planned outages from end users. To attain high levels of continuous availability and near-transparent D/R, the solution should be based on 3

5 geographical clusters and data mirroring. These technologies are the backbone of the Geographically Dispersed Parallel Sysplex (GDPS ) solution. GDPS offers different solutions based on the underlying mirroring technology: The GDPS solution, based on IBM System Storage Metro Mirror (formally called Peer-to- Peer Remote Copy, or PPRC), is referred to as GDPS/PPRC. GDPS/PPRC HyperSwap Manager, also based upon Metro Mirror, is a disk availability and entry level disaster recovery solution. The GDPS solution based on IBM System Storage z/os Global Mirror (formally called Extended Remote Copy, or XRC), is referred to as GDPS/XRC. The GDPS solution based on IBM System Storage Global Mirror is referred to as GDPS/Global Mirror. Combining synchronous and asynchronous technology to form three site solutions such as GDPS Metro/Global Mirror or GDPS Metro/z/OS Global Mirror which combine either Metro Mirror and Global Mirror or Metro Mirror and z/os Global Mirror GDPS/PPRC is designed with the attributes of a continuous availability and disaster recovery solution. Metro Mirror is a hardware solution that synchronously mirrors data residing on a set of disk volumes, called the primary volumes, to secondary disk volumes in a secondary site up to 300 km away. Since IBM Parallel Sysplex clustering technology is designed to enable resource sharing and dynamic workload balancing, enterprises can now dynamically manage workloads across multiple sites which can enable them to achieve high levels of availability. GDPS/PPRC is application and data independent. When managing the data it can be used to provide a consistent recovery for z/os as well as non-z/os data. This is important for a common situation when a multi-tier application has dependencies upon multiple operating system architectures. It is not enough that z/os data is consistent, but it needs to be consistent with non-ibm System z data to allow rapid business resumption. GDPS/PPRC HyperSwap manager provides either a single-site near-continuous availability solution or an entry level multisite disaster recovery solution at a cost-effective price. One can migrate from a GDPS/PPRC HyperSwap Manager implementation to the full-function GDPS/PPRC capability as business requirements demand shorter recovery time objectives. GDPS/XRC is a highly scalable asynchronous remote copy solution for z/os and Linux on System z data. Based upon z/os Global Mirror, it is a combined hardware and software asynchronous remote copy solution. The application I/O is signaled completed when the data update to the primary storage is completed. Subsequently, a z/os component called System Data Mover (SDM), typically running in the recovery site (site 2), asynchronously offloads data from the primary storage subsystem s cache and updates the secondary disk volumes. 4

6 Since z/os Global Mirror is an asynchronous data replication technique, the secondary site can be thousands of miles from the primary site connected by telecommunication lines. GDPS/Global Mirror is an asynchronous remote copy solution for z/os and non-z/os data. Global Mirror is a hardware based asynchronous mirroring solution that is designed to maintain a consistent copy of data at virtually unlimited distances with minimal impact to application response time. As seen in Figure 3, when an application issues a write request to a primary device that is part of the mirroring configuration, the I/O completes as soon as the request is successfully received by the primary control unit. Soon after, the updated data is sent to the secondary disk subsystem. At a user-controlled interval, primary disk updates will be drained to the secondary disk and a FlashCopy is performed between the secondaries and the associated FlashCopy target volumes. This creates a consistent copy of the data that can be used for recovery. Global Mirror now resumes sending data to the secondaries. All this processing is done under the control of code in the storage servers. Global Mirror Primary GM Secondary FlashCopy Source FlashCopy Target Asynchronous remote copy FlashCopy A B C Local Site Remote Site Automatic Cycle in a Global Mirror Session 1. Application sends a write request 2. Write complete signalled to the appliation 3. Update is sent to the remote B-disk asynchronously 4. Create point-in-time copy consistency group on A-disk after predefined time. Write IOs queued for short period of time. Usually < 3 ms 5. Drain remaining CG data to B-disk 6. FlashCopy CG to C-disk Figure 3: Global Mirror Configuration 5

7 Global Mirror is data independent. It can be used to provide a consistent recovery for z/os, z/vm, Linux, as well as non-system z data. This is important when a multi-tier application has dependencies upon multiple operating system architectures. For the remainder of this paper, the terms GDPS/PPRC, GDPS/PPRC HM, GDPS/XRC, and GDPS/Global Mirror will be used when there is a need to differentiate the three solutions. The term GDPS will be used to discuss items common to all three solutions. The differences between the GDPS/PPRC, GDPS/PPRC HM, GDPS/XRC, and GDPS/Global Mirror solutions should be carefully reviewed before deciding which solution best fits your business objectives. A number of GDPS customers have reported that when running D/R tests, they have experienced significant reductions to the recovery time window and have experienced no data loss or minimal data loss after the recovery. GDPS works even in a real disaster. A customer's data center experienced a fire, which generated a GDPS TAKEOVER alert. A short time after the decision was made to execute the site TAKEOVER script, the production applications were up and running in site 2. Refer to the section, GDPS/PPRC at Work in a Real Disaster for a more detailed description. Lessons learned about IT survival The events of September 11, 2001 in the United States of America have underlined how critical it is for businesses to be ready for disasters. The Federal Reserve, the Office of the Comptroller of the Currency, the Securities and Exchange Commission, and the New York State Banking Department (the agencies) met with industry participants to analyze the lessons learned from the events of September 11. The agencies released an interagency white paper (referenced in the section, Additional Information) on practices to strengthen the resilience of the US financial system. The following is a summary of lessons the agencies learned about IT service continuity: Geographical separation of facilities and resources is critical to maintaining business continuity. Any resource that cannot be replaced from external sources within the Recovery Time Objective1 (RTO) should be available within the enterprise, in multiple locations. This not only applies to buildings and hardware resources, but also to employees and data, since planning employee and data survival is very critical. Allowing staff to work out of a home office should not be overlooked as one way of being D/R ready. Depending on the RTO and Recovery Point Objective2 (RPO) RTO and/or RPO are typically expressed in hours or minutes it may be necessary for some enterprises to implement an in-house D/R solution. If this is the case, the facilities required to achieve geographical separation may need to be owned by the enterprise. 2 Recovery Time Objective: a metric for how long it takes to recover the application and resume operations after an outage - planned or unplanned. 3 Recovery Point Objective: a metric for how much data is lost, or the actual recovery point to which all data is current and consistent. 6

8 The installed server capacity at the second data center can be used to meet normal day-today data processing needs and fallback capacity can be provided either by prioritizing workloads (production, test, development, data mining) or by implementing capacity upgrades based on changing a license agreement, rather than by installing additional capacity. Disk resources need to be duplicated for disk data that is mirrored. Recovery procedures must be well-documented, tested, maintained and available after a disaster. Data backup and/or data mirroring must run like clockwork all the time. It is highly recommended that the D/R solution be based on as much automation as possible. In case of a disaster, key skills may not be available to restore I/T services. An enterprise s critical service providers, suppliers and vendors may be affected by the same disaster, therefore, enter into a discussion with them about their D/R readiness. GDPS, based on geographical separation and automation, is positioned to provide a total business continuity solution for the entire IBM platform. What is a GDPS? GDPS is an integrated, automated application and data availability solution designed to provide the capability to manage the remote copy configuration and storage subsystem(s), automate Parallel Sysplex operational tasks, and perform failure recovery from a single point of control, thereby helping to improve application availability. GDPS is independent of the transaction manager (e.g., CICS TS, IMS, WebSphere ) or database manager (e.g., DB2, IMS, and VSAM) being used, and is enabled by means of key IBM technologies and architectures: Base or Parallel Sysplex Tivoli NetView for z/os System Automation for z/os Disk control units such as IBM System Storage DS6000 and DS8000 series and IBM TotalStorage Enterprise Storage Server (ESS) that support: Metro Mirror architecture for GDPS/PPRC z/os Global Mirror architecture for GDPS/XRC Global Mirror architecture for GDPS/Global Mirror Peer-to-Peer Virtual Tape Server (PtP VTS) that supports Virtual Tape Server Remote Copy architecture 7

9 GDPS supports the synchronous (Metro Mirror) as well as the asynchronous [z/os Global Mirror (XRC) and Global Mirror] forms of data replication. GDPS also supports Peer-to-Peer Virtual Tape Server (PtP VTS) form of remote copying tape data. The GDPS solution is a nonproprietary solution, working with IBM as well as Other Equipment Manufacturer (OEM) disk and tape vendors, as long as the vendor meets the specific functions of the Metro Mirror, z/os Global Mirror, Global Mirror, and PtP VTS architectures required to support GDPS functions as documented on the GDPS Web site: ibm.com/systems/z/gdps/getstarted Need for Data Consistency Data consistency across all secondary volumes spread across any number of storage subsystems is essential in providing data integrity and the ability to do a normal database restart in the event of a disaster. The main focus of GDPS automation is whatever happens in site 1, to allow the secondary copy of the data in site 2 to be data consistent to allow rapid restart. GDPS is designed so any failure in site 2 does not effect applications running in site 1. Data consistent means that, from an application s perspective, the secondary disks contain all updates until a specific point in time, and no updates beyond that specific point in time. Time consistent data in the secondary site allow applications to restart in the secondary location without having to go through a lengthy and time-consuming data recovery process. Data recovery involves restoring image copies and logs to disk and executing forward recovery utilities to apply updates to the image copies. This process can take many hours or days. Since with GDPS applications only need to be restarted, an installation can be up and running quickly, even when the primary site (site 1) has been rendered totally unusable. GDPS/PPRC uses a combination of storage subsystem and Parallel Sysplex technology triggers to capture, at the first indication of a potential disaster, a data consistent secondary site (site 2) copy of the data, using the PPRC freeze function. The freeze function, initiated by automated procedures, is designed to freeze the image of the secondary data at the very first sign of a disaster, even before any database managers are made aware of I/O errors. This can prevent the logical contamination of the secondary copy of data that would occur if any storage subsystem mirroring were to continue after a failure that prevents some, but not all secondary volumes from being updated. Data consistency in a GDPS/XRC environment is provided by the Consistency Group (CG) processing performed by the System Data Mover (SDM). The CG contains records that have their order of update preserved across multiple Logical Control Units within a storage subsystem and across multiple storage subsystems. The SDM manages consistency based on 8

10 each write I/O to XRC primary volumes being time-stamped by a common clock (Sysplex Timer ) and all hosts in the Parallel Sysplex cluster running off that same clock source. Data consistency for GDPS/Global Mirror is provided by the control units periodically halting updates to disk so the secondary disk at the remote site can receive all updates as of a point in time. The data on the secondary disk is then flash copied to another set of disk to provide a consistent copy of the data that can be used when recovering from a disaster. Providing data consistency enables the secondary copy of data to perform normal restarts (instead of performing database manager recovery actions). This is the essential design element of GDPS in helping to minimize the time to recover the critical workload, in the event of a disaster in site 1. GDPS Systems GDPS consists of production systems and controlling systems. The production systems execute the mission critical workload. There must be sufficient processing resource capacity (typically in site 2), such as processor capacity, main storage, and channel paths available that can quickly be brought on-line to restart a system's or site's critical workload (typically by terminating one or more systems executing expendable, non-critical work and acquiring its processing resource). The Capacity BackUp (CBU) feature, available on the IBM System z products could provide additional processing power, which can help you to achieve cost savings. The CBU feature has the ability to increment capacity temporarily, when capacity is lost elsewhere in the enterprise. CBU adds Central Processors (CPs) to the available pool of processors and is activated only in an emergency. GDPS-CBU management automates the process of dynamically adding reserved CPs, thereby helping to minimize manual customer intervention and the potential for errors. The outage time for critical workloads can potentially be reduced from hours to minutes. Similarly, GDPS-CBU management can also automate the process of dynamically returning the reserved CPs when the temporary period has expired. The controlling system coordinates GDPS processing. By convention all GDPS functions are initiated and coordinated by the controlling system. All GDPS systems run GDPS automation based upon Tivoli NetView for z/os and Tivoli System Automation for z/os. Each system can monitor the sysplex cluster, Coupling Facilities, and storage subsystems and maintain GDPS status. GDPS automation can coexist with an enterprise's existing automation product. 9

11 Need for Automation Implementing remote copy, tape remote copy, FlashCopy, and so on, are necessary prerequisites to be able to recover from a disaster given stringent Recovery Time and Recovery Point objectives. However, they are only enabling technologies. In order to achieve the stringent objectives, it is necessary to tie those technologies together with automation. In an average computer room immediately following a basic system failure, all the phones are ringing, every manager within reach moves in to find out when everything will be recovered, the operators are frantically scrambling for procedures that are more than likely out of date, and the Systems Programmers are all vying with the operators for control of the consoles. In short - chaos! Imagine instead a scenario where the only manual intervention is to confirm that one should proceed. From that point on, the system will recover itself using well tested procedures. It responds to messages at system speed. You don t need to worry about out of date procedures being used. The operators can concentrate on handing calls and queries from the assembled managers. And the Systems Programmers can concentrate on pinpointing the cause of the outage, rather than trying to get everything up and running again. And all of this is just for a system outage. In a disaster recovery situation one also needs to invoke Capacity Back-Up (CBU), remove failed systems from the sysplex, switch disk to use secondaries, reverse the remote copy, clean up CF structures and switch policies, modify activation profiles to come up on the second site using the correct IPL volume, switch network resources, IPL failed systems, and so on. Training staff takes time. People come and go. You cannot be sure that the staff that took part in the last disaster recovery test will be on hand to drive recovery from this real disaster. In fact, depending on the nature of the disaster, your skilled staff may not even be available to drive the recovery. Even for the day-to-day activities in setting up and modifying a system for planned activities, managing a remote copy environment is complicated. One needs to define the remote copy pairs, establish paths, establish pairs, constantly monitor if remote copy is ever broken, then re-synchronize and re-establish remote copy. This needs to be done for each of the thousands of volumes. The use of automation removes these concerns as potential pitfalls to your successful recovery. 10

12 GDPS: The e-business Availability Solution GDPS/PPRC GDPS/PPRC is designed to manage and protect IT services by handling planned and unplanned exception conditions, and maintain data integrity across multiple volumes and storage subsystems. By managing both planned and unplanned exception conditions, GDPS/PPRC can help to maximize application availability and provide business continuity. GDPS/PPRC is capable of the following attributes: Near continuous Availability solution Near transparent D/R solution Recovery Time Objective (RTO) less than an hour Recovery Point Objective (RPO) of zero (optional) Protects against localized area disasters (distance between sites limited to 100 km fiber) The physical topology of a GDPS/PPRC, shown in Figure 4: GDPS/PPRC, consists of a base or Parallel Sysplex cluster spread across two sites (known as site 1 and site 2 in this paper) separated by up to 100 kilometers (km) of fiber approximately 62 miles with one or more z/os systems at each site. NETWORK ETR or STP NETWORK SITE 2 ETR or STP SITE 1 Figure 4: GDPS/PPRC 11

13 The multisite sysplex cluster must be configured with redundant hardware in each site and the cross-site connections must be redundant. All critical data resides on storage subsystem(s) in site 1 (the primary copy of data) and is mirrored to the storage subsystem(s) in site 2 (the secondary copy of data) via PPRC, also known as Metro Mirror, synchronous remote copy. Customers have the capability to configure GDPS/PPRC with up to 100 km of fiber between two sites. An immediate advantage of this extended distance is to potentially decrease the risk that the same disaster will affect both sites, thus permitting customers to recover their production applications at another site. The use of Server Time Protocol (STP) is recommended whenever the two sites are more than 40 km fiber distance apart as well as for any new sysplex installations. Planned Reconfiguration support GDPS/PPRC planned reconfiguration support automates procedures performed by an operations center. These include standard actions to: 1) Quiesce a system s workload and remove the system from the Parallel Sysplex cluster (i.e., stop the system prior to a hardware change window); 2) IPL a system (i.e., start the system after a hardware change window); and 3) Quiesce a system's workload, remove the system from the Parallel Sysplex cluster, and re- IPL the system (e.g., recycle a system to pick up software maintenance). Standard actions can be initiated against a single system or a group of systems. With the introduction of HyperSwap, you now have the ability to perform disk maintenance and planned site maintenance without requiring applications to be quiesced. Additionally, GDPS/PPRC provides customizable scripting capability for user defined actions (e.g., planned disk maintenance or planned site switch in which the workload is switched from processors in site 1 to processors in site 2). All GDPS functions can be performed from a single point of control, which can help simplify system resource management. Panels are used to manage the entire remote copy configuration, rather than individual remote copy pairs. This includes the initialization and monitoring of the remote copy volume pairs based upon policy and performing routine operations on installed disk and tape storage subsystems. GDPS can also perform standard operational tasks, and monitor systems in the event of unplanned outages. 12

14 Unplanned Reconfiguration support GDPS/PPRC s unplanned reconfiguration support not only can automate procedures to handle site failures, but can also help minimize the impact and potentially mask a z/os system, processor, Coupling Facility, disk or tape failure, based upon GDPS/PPRC policy. If a z/os system fails, the failed system and workload can be automatically restarted. If a processor fails, the failed system(s) and their workload can be restarted on other processors. Near Continuous Availability of data with HyperSwap GDPS in the PPRC environment supports HyperSwap. This function is designed to broaden the near continuous availability attributes of GDPS/PPRC by extending the Parallel Sysplex redundancy to disk subsystems. The HyperSwap function can help significantly reduce the time needed to switch to the secondary set of disks while keeping the z/os systems active, together with their applications. The HyperSwap function has been enhanced to exploit the Metro Mirror Failover/Failback (FO/FB) function. For planned reconfigurations, FO/FB may reduce the overall elapsed time to switch the disk subsystems, thereby reducing the time that applications are unavailable to users. This is demonstrated by the benchmark measurements discussed below. For unplanned reconfigurations, Failover/Failback allows the secondary disks to be configured in the suspended state after the switch and record any updates made to the data. When the failure condition has been repaired, resynchronizing back to the original primary disks requires only the changed data to be copied, thus eliminating the need to perform a full copy of the data. The window during which critical data is left without Metro Mirror protection following an unplanned reconfiguration is thereby minimized. The Planned HyperSwap function is designed to provide the ability to transparently switch all primary disk subsystems with the secondary disk subsystems for planned reconfigurations. During a planned reconfiguration, HyperSwap can provide the ability to perform disk configuration maintenance and planned site maintenance without requiring any applications to be quiesced. Large configurations can be supported, as HyperSwap is designed to provide capacity and capability to swap a large number of disk devices very quickly. The important ability to re-synchronize incremental disk data changes, in both directions, between primary/ secondary disks is provided as part of this function. Benchmark measurements using HyperSwap for Planned Reconfiguration The IBM test facility had performed a benchmark of the Failover/Failback capability. In a configuration of 6545 volume pairs (19.6 TB data), the entire switch took 15 seconds for a planned reconfiguration. z/os Processing then continued otherwise uninterrupted. 13

15 Using the GDPS/PPRC HyperSwap technology is a significant step forward in achieving continuous availability. The benefits in our GDPS environments are that planned switches of the disk configuration took seconds without application outage. The user impact time of unplanned disk reconfigurations was 3-8 seconds; with 8 seconds to swap a configuration of over 4,900 PPRC volume pairs. Without HyperSwap planned and unplanned reconfigurations had resulted into a service outage of almost two hours in our Sysplex/GDPS with 10 systems." Wolfgang Dungl, Manager of Availability, Capacity and Performance Management Wolfgang Schott, GDPS Project Manager, it-austria The Unplanned HyperSwap function is designed to transparently switch to use secondary disk subsystems which contain mirrored data consistent with the primary data, in the event of unplanned outages of the primary disk subsystems or a failure of the site containing the primary disk subsystems (site 1). With Unplanned HyperSwap support: Production systems can remain active during a disk subsystem failure. Disk subsystem failures will no longer constitute a single point of failure for an entire sysplex. Production systems can remain active during a failure of the site containing the primary disk subsystems (site 1), if applications are cloned and exploiting data sharing across the two sites. Even though the workload in site 2 will need to be restarted, an improvement in the Recovery Time Objective (RTO) is accomplished. Benchmark measurements using HyperSwap for Unplanned Reconfiguration An unplanned disk reconfiguration test using HyperSwap with failover/failback, conducted at the GDPS solution center demonstrated that the user impact time was only 13 seconds to swap a configuration of 6545 volumes / 19.6 TB of ESS and DS8000 disks while keeping the applications available, compared to typical results of minutes without HyperSwap. What this benchmark does not show is the failover/failback capability to only copying the changed data instead of the entire disk during the resynchronization process. This can save significant time and network resources. 14

16 GDPS/PPRC HyperSwap Manager GDPS/PPRC HyperSwap Manager (GDPS/PPRC HM) expands System z Business Resiliency to customers by providing a single-site near continuous availability solution as well as a multi-site entry-level disaster recovery solution. Within a single site, GDPS/PPRC HyperSwap Manager extends Parallel Sysplex availability to disk subsystems by masking planned and unplanned disk outages caused by disk maintenance and disk failures. It also provides management of the data replication environment and automates switching between the two copies of the data without causing an application outage, therefore providing near-continuous access to data. Figure 5 shows an example of a GDPS/PPRC HM configuration. In the multisite environment, GDPS/PPRC HyperSwap Manager provides an effective entrylevel availability and disaster recovery offering for those IBM System z customers that have the need for very high levels of data availability. Value is further enhanced by being able to use specially priced Tivoli System Automation and NetView products. In addition, a customer can migrate to the full function GDPS/PPRC capability across multiple sites as business requirements demand shorter Recovery Time Objectives provided by a second site. The initial investment in GDPS/PPRC HM is protected when customers choose to move to full-function GDPS/PPRC by leveraging the existing GDPS/PPRC HM implementation and skills. GDPS/PPRC HM simplifies the control and management of the Metro Mirror (PPRC) environment for both System z and non-system z data. This reduces storage management costs while reducing the time required for remote copy implementation. GDPS/PPRC HM provides support for FlashCopy. GDPS/PPRC HM can be set up to automatically take a FlashCopy of the secondary disks before resynchronizing the primary and secondary disks following a Metro Mirror suspension event, helping ensure a consistent set of disks are preserved should there be a disaster during the re-synch operation. 15

17 Figure 5: GDPS/PPRC HyperSwap Manager Configuration Near continuous availability of data within a single site A Parallel Sysplex environment has been designed to reduce outages by replicating hardware, operating systems and application components. In spite of this redundancy having only one copy of the data is an exposure. GDPS/PPRC HyperSwap Manager is designed to provide continuous availability of data by masking disk outages caused by disk maintenance and/or failures. For example, if normal processing is suddenly interrupted when one of the disk subsystems experiences a hard failure, thanks to GDPS the applications are masked from this error because GDPS detects the failure and autonomically invokes HyperSwap. The production systems continue using data from the mirrored secondary volumes. Disk maintenance can also be similarly performed without application impact by executing HyperSwap command. Near continuous availability of data/disaster Recovery solution at metropolitan distances In addition to the single site capabilities, in a two site configuration GDPS/PPRC HyperSwap Manager provides an entry-level disaster recovery capability at the recovery site. GDPS/PPRC HM uses the Freeze function described in the section, Need for Data Consistency. The Freeze 16

18 function is designed to provide a consistent copy of data at the recovery site from which production applications can be restarted. The ability to simply restart applications helps eliminate the need for lengthy database recovery actions. Automation to stop and restart the operating system images available with the full-function GDPS/PPRC is not included with GDPS/PPRC HyperSwap Manager. GDPS/XRC z/os Global Mirror (also known as Extended Remote Copy, or XRC) is a combined hardware and z/os software asynchronous remote copy solution. GDPS/XRC includes automation to manage remote copy pairs and automates the process of recovering the production environment with limited manual intervention, including invocation of CBU. This provides the ability to perform a controlled site switch for a planned or unplanned site outage and gives significant value in reducing the duration of the recovery window and requiring less operator interaction. GDPS/XRC is capable of the following attributes: Disaster recovery solution RTO between an hour to two hours RPO less than one minute Protects against localized as well as regional disasters (distance between sites is unlimited) Minimal remote copy performance impact The physical topology of a GDPS/XRC, shown in Figure 6, consists of production system(s) in site 1. The production systems could be a single system, multiple systems sharing disk, or a base or Parallel Sysplex cluster3. Site 2, (the recovery site) can be located at a virtually unlimited distance from site 1 (the production site). 3 Note that if there is a base or Parallel Sysplex cluster in the production site, it does not need to span across sites 1 and 2. 17

19 Figure 6: GDPS/XRC During normal operations, the z/os Global Mirror System Data Mover (one or more) execute in site 2 and are in a base or Parallel Sysplex environment with the GDPS controlling system (refer to section, GDPS Systems for a definition of the GDPS controlling system). All critical data resides on storage subsystem(s) in site 1 (the primary copy of data) and is mirrored to the storage subsystem(s) in site 2 (the secondary copy of data) via z/os Global Mirror asynchronous remote copy. Planned Reconfiguration support All the planned reconfiguration actions described in the section, GDPS/PPRC are provided by GDPS/XRC for the System Data Mover (SDM) Sysplex in site 2. For example, GDPS/XRC will manage the temporary relocation of the SDM, if it is needed. By managing the SDM Sysplex, GDPS/XRC can also manage the z/os Global Mirror remote copy configuration. As noted in the section, Lessons learned about IT survival, it is recommended that the D/R solution be based on as much automation as possible to minimize the dependency on key skills being available to recover from a disaster. GDPS/XRC is designed to automate the process of recovering the production environment with minimal manual intervention, which can provide significant value in minimizing the duration of the recovery window. 18

20 GDPS: The e-business Availability Solution Recent support with GDPS/XRC includes Zero Suspend Flash Copy. This allows a consistent flash copy of the data at the recovery site to be made without requiring the z/os Global Mirror replication to be suspended and restarted, preserving the disaster recovery environment. With DS8000 storage and IBM System z10 Enterprise Class (z10 EC ), Extended Distance FICON can help avoid degradation of performance at extended distances by implementing a new protocol for persistent Information Unit (IU) pacing. This can help reduce the need for channel-extender equipment, or allow you to choose lower-cost channel extenders. All of this helps reduce the total cost of ownership in z/os Global Mirror or three site MzGM configurations. GDPS/Global Mirror Global Mirror is a hardware asynchronous remote copy solution. GDPS/Global Mirror includes automation to manage remote copy pairs, perform planned disk reconfiguration activities, automate IPL and shutdown of LPARs, as well as automate the process of recovering the production environment after a disaster with limited manual intervention, including invocation of CBU, thus providing significant value in reducing the duration of the recovery window and requiring less operator interaction. The physical topology of a GDPS/GM, shown in Figure 7, consists of production system(s) in site 1. While the production LPARs could be in any System z configuration, GDPS/GM can also manage non-system z data. GDPS/GM can manage this non-system z data in the same consistency group as the System z data, from a single point of control. Site 2, (the recovery site) can be located at a virtually unlimited distance from site 1 (the production site). CF CF K K P1 Nonz Global Mirror R R P1 Bkup Non-z Bkup Site1 KgA B A Nonz Nonz C A Nonz Recovery Site Figure 7: GDPS/Global Mirror Configuration GDPS/Global Mirror is capable of the following attributes: 19

21 Disaster recovery solution for System z and non-system z data RTO between an hour to two hours RPO less than one minute Protects against regional disasters (distance between sites is unlimited) Minimal remote copy performance impact Three Site Solutions Many businesses require the benefits of both synchronous and asynchronous remote copy. Synchronous remote copy using GDPS/PPRC and GDPS/PPRC HM provides benefits such as near-continuous availability using HyperSwap and the ability to configure for zero data loss. Asynchronous remote copy using GDPS/XRC or GDPS/Global Mirror provides benefits such as protection from regional disasters with little to no application impact. To provide for this requirement, GDPS supports two solutions based upon a three site configuration, These solutions help provide maximum availability across the widest range of possible scenarios. 1. GDPS/PPRC or GDPS/PPRC HM combined with GDPS/XRC is called GDPS Metro/ z/os Global Mirror, or GDPS/MzGM. The GDPS/MzGM solution is a multi-target solution. The primary (A) disk replicates to the Metro Mirror (B) disk and also the remote z/os Global Mirror (C) disk. If the A disk is unavailable, the z/os Global Mirror session is quickly established from the (B) disk to the (C) disk to preserve disaster recovery protection. 2. GDPS/PPRC or GDPS/PPRC HM combined with GDPS/Global Mirror is called GDPS Metro/Global Mirror, or GDPS/MGM. GDPS/MGM is a cascading solution that also provides a solution for both System z and non-z data. The primary (A) disk replicates to the Metro Mirror (B) disk, which in turn replicates to the remote Global Mirror (C) disk. If the (B) disk becomes unavailable, the Global Mirror session is quickly established from the (A) disk to the (C) disk. This again preserves the disaster recovery environment. 20

22 Functions common to multiple GDPS solutions The following functions are supported by multiple GDPS solutions: Peer-to-Peer Virtual Tape Server (PtP VTS) support GDPS also supports Peer-to-Peer Virtual Tape Server. By extending GDPS support to data resident on tape, the GDPS solution is intended to provide continuous availability and near transparent business continuity benefit for both disk and tape resident data. The PtP VTS provides a hardware-based duplex tape solution and GDPS can automatically manage the duplexed tapes in the event of a planned site switch or a site failure. Control capability has been added to allow GDPS to freeze copy operations, so that tape data consistency can be maintained across GDPS managed sites during a switch between the primary and secondary VTSs. PtP VTS is currently supported by GDPS/XRC and GDPS/PPRC only. FlashCopy support FlashCopy, available on the IBM System Storage DS Family and IBM System Storage Enterprise Storage Server (ESS), is designed to provide an instant point-in-time copy of the data for application usage such as backup and recovery operations. FlashCopy can enable you to copy or dump data while applications are updating the data. FlashCopy before resynchronization is automatically invoked (based upon policy) whenever a resynchronization request is received. This function provides a consistent data image to fall back to, in the rare event that a disaster should occur while resynchronization is taking place. FlashCopy can also be user-initiated at any time. Customers can then use the tertiary copy of data to conduct D/R testing while maintaining D/R readiness, perform either test/development work, shorten batch windows, etc. GDPS automation is designed to help initiate and manage different flavors of FlashCopy data, including COPY, NOCOPY, Incremental, and Space Efficient FlashCopy. Support for Heterogeneous Environments Management of IBM System z Operating Systems In addition to managing images within the base or Parallel Sysplex cluster, GDPS can now also manage a customer's other System z production operating systems and data these include z/os, Linux for System z, z/vm, and VSE/ESA. The operating systems have to run on servers that are connected to the same Hardware Management Console (HMC) Local Area Network (LAN) as the Parallel Sysplex cluster images. For example, if the volumes associated with the Linux images are mirrored using PPRC, GDPS can restart these images as part of a planned or unplanned site reconfiguration. The Linux for System z images can either run as a logical partition (LPAR) or as a guest under z/vm. 21

23 GDPS/PPRC, GDPS/PPRC HM, and GDPS/GM Open LUN Management GDPS/PPRC, GDPS/PPRC HyperSwap Manager, and GDPS/Global Mirror technology have been extended to manage a heterogeneous environment of System z and distributed systems Logical Unit Numbers (LUNs). If installations share their disk subsystems between the System z and distributed systems platforms, GDPS/PPRC, GDPS/PPRC HM, and GDPS/Global Mirror can manage the Metro Mirror or Global Mirror remote copy configurations, and FlashCopy for distributed systems storage. GDPS/PPRC and GDPS/Global Mirror are also designed to provide data consistency across both System z and distributed Systems data. This allows GDPS to be a single point of control to manage business resiliency across multiple tiers in the infrastructure, improving cross-platform system management and business processes. GDPS/PPRC Multiplatform Resiliency for System z GDPS/PPRC has been enhanced to provide a function called GDPS/PPRC Multiplatform Resiliency for System z, also referred to as xdr. This function is especially valuable for customers who share data and storage subsystems between z/os and either SUSE or RedHat Linux z/vm guests on System z or SUSE Linux running native on System z LPARs. For example, an application server running on Linux on System z and a database server running on z/os. With a multi-tiered architecture, there is a need to provide a coordinated near Continuous Availability/Disaster Recovery solution for both z/os and Linux on System z. GDPS/PPRC can provide this capability when Linux is running as a z/vm guest or native. Using the HyperSwap function so that the virtual device associated with one real disk can be swapped transparently to another disk, HyperSwap can be used to switch to secondary disk storage subsystems mirrored by PPRC (Metro Mirror). If there is a hard failure of a storage device, GDPS coordinates the HyperSwap with z/os for continuous availability spanning the multitiered application. For site failures, GDPS invokes the Freeze function for data consistency and rapid application restart, without the need for data recovery. HyperSwap can also be helpful in data migration scenarios to allow applications to migrate to new disk volumes without requiring them to be quiesced. 22

24 GDPS/PPRC will provide the reconfiguration capabilities for the Linux on System z servers and data in the same manner as for z/os systems and data. To support planned and unplanned outages, GDPS provides the recovery actions such as the following examples: Re-IPL in place of failing operating system images Site takeover/failover of a complete production site Coordinated planned and unplanned HyperSwap of disk subsystems, transparent to the operating system images and applications using the disks Linux node or cluster failures Transparent disk maintenance or failure recovery with HyperSwap across z/os and Linux applications Data consistency with freeze functions across z/os and Linux Distributed Cluster Manager Distributed Cluster Management (DCM) enables coordination of planned and unplanned actions between System z and distributed servers clustered using clustering software. A GDPS DCM agent running in each distributed cluster will provide advisory and coordination functions between GDPS and one or more distributed clusters. The advisory functions will provide the capability of continuous heartbeat and status gathering to alert the support staff about any events that may prevent recovery at the time of an outage. The coordination functions will allow workflow integration for takeover and recovery testing, cross-platform monitoring to maintain recovery capability and cross-platform recovery management to provide an automated enterprise-level rapid recovery in the case of an outage. DCM support is provided for Symantec Veritas Cluster Server (VCS) with GDPS/PPRC, GDPS/XRC, and GDPS/GM, and for Tivoli System Automation Application Manager (AppMan) clusters with GDPS/PPRC. The distributed cluster manager such as VCS or AppMan can monitor the status of applications on multiple operating systems such as IBM AIX, Sun-Solaris, HP-UX, Linux, and VMware based systems. It can them automatically move them to another server in the event of a fault. This is designed to be coordinated with GDPS from a central point of control. 23

25 Recent Enhancements in GDPS V3.6 A summary of the enhancements announced with GDPS V3.6 is listed below. Please refer to IBM US announcement letter , IBM GDPS V3.6: Enterprise-wide infrastructure availability and disaster recovery, dated February 24, 2009 for items announced as Preview or Statement of Directions. Improved coordinated disaster recovery across heterogeneous platforms by: Distributed Cluster Management (DCM) support for GDPS/GM. This is designed to allow the management and coordination of planned and unplanned outages across distributed servers which may be clustered using clustering solutions, and the System z workloads that GDPS is responsible for. DCM support for GDPS/GM is available for VCS based clustering solutions. GDPS/PPRC Multiplatform Resiliency for System z (xdr) support for LSS Sharing between z/vm 0LPARs. This is designed to support mulitple z/vm LPARs sharing the same disk Logical Subsystem with GDPS/PPRC. It also allows multiple z/vm LPARs to share the same disk using the z/vm Cross System Extension (CSE) function. Increased availability with: Reduced-impact intial copy and resynchronization of Metro Mirror volumes. This reduces the exposure window where the environment is without Freeze or HyperSwap protection by reducing the need to throttle down the copy process. There is no need to schedule copies to off-shift times to run. Rather, they can now run any time of the day without impacting production work. Copies are initiated using asynchronous Global Copy. GDPS then monitors progress of the copy operation. When the volumes are near full duplex state, GDPS will convert the replication from asynchronous Global Copy to synchronous Metro Mirror copy. Remote Pair FlashCopy support. This is designed to provide the capability to allow a FlashCopy relationship where the FlashCopy target device is a Metro Mirror primary device. The value of FlashCopy can now be combined with the value of HyperSwap. GDPS/PPRC timer support: GDPS recovery times are improved for events that impact the primary time source for the sysplex, whether the time source is Server Time Protocol (STP) or External Time Reference (ETR) based. These enhancements allow the GDPS controlling system (K-sys) to continue processing, even when the server it is running on loses its time source and becomes unsynchronized. The K-sys is will be able to complete any Freeze or HyperSwap processing it may have started instead of being in a disabled WTOR state. Normally, a loss of synchronization with the sysplex timing source will generate a disabled console WTOR that suspends all processing on the LPAR, until a response is made to the WTOR. This requires support planned to be available with z/os V1.11 in 3Q09. Two K-Systems support: GDPS/PPRC Multiplatform Resiliency for System z (xdr) allows GDPS to manage Linux guests on z/vm and native Linux on System z LPARs with the same quality of service as for z/os LPARs. This includes support for HyperSwap for Linux data, and the ability of GDPS to manage Linux and z/vm 24