Assignment No. SAN. Title. Roll No. Date. Programming Lab IV. Signature

Transcription

1 Assignment No. Title (A-6) SAN Roll No. Class T.E. Date Subject Programming Lab IV Signature

2 Assignment no: (A-6) Title: Study of Storage Area Network (SAN). Problem Statement: Design and Setup LAN with Star topology to access SAN. The SAN must have DSP data, Text Data, Multimedia Data available for the access. Prerequisites: Basics of Networking. Objectives: 1] To learn concept of Storage Area Network. 2] To study how does Storage Area Network work? Theory: Basics of SAN: SAN presents shared pools of storage devices to multiple servers. Each server can access the storage as if it were directly attached to that server. A SAN supports centralized storage management. SANs make it possible to move data between various storage devices, share data between multiple servers, and backup and restore data rapidly and efficiently. In addition, a properly configured SAN facilitates both disaster recovery and high availability. A storage area network (SAN) is a high -performance subnet, probably (but not necessarily) based on fiber channel, whose primary purpose is the transfer of data between computer systems and storage elements and among multiple storage elements. SAN as an extended and shared storage bus. A SAN consists of a communication infrastructure, which provides physical connections, and a management layer, which organizes the connections, storage elements, and computer systems so that data transfer is secure and robust.

3 Fig 1: SAN block diagram SAN Component Overview: A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to enhance storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices to the operating system. A SAN typically has its own network of storage devices that are generally not accessible through the local area network (LAN) by other devices. Ref. fig 2 on next page. In its simplest form, a SAN consists of one or more servers (1) attached to a storage array (2) using one or more SAN switches. Each server might host numerous applications that require dedicated storage for applications processing. SAN Switches(3): SAN switches connect various elements of the SAN. In particular, they might connect hosts to storage arrays. SAN switches also allow administrators to set up path redundancy in the event of a path failure from host server to switch or from storage array to switch. Fabric(4): The SAN fabric is the actual network portion of the SAN. When one or more SAN switches are connected, a fabric is created. The FC protocol is used to communicate over the entire network. A SAN can consist of multiple interconnected fabrics. Even a simple SAN often consists of two fabrics for redundancy

4 Connections: Host Bus Adapters (5) and Storage Processors (6): Host servers and storage systems are connected to the SAN fabric through ports in the fabric. A host connects to a fabric port through an HBA. Storage devices connect to fabric ports through their storage processors. How a SAN Works: The SAN components interact as follows: Fig 2: SAN components 1) When a host wants to access a storage device on the SAN, it sends out a block based access request for the storage device. 2) SCSI commands are encapsulated into FC packets. The request is accepted by the HBA for that host and is converted from its binary data form to the optical form required for transmission on the fiber optic cable. 3) At the same time, the request is packaged according to the rules of the FC protocol. 4) The HBA transmits the request to the SAN. 5) Depending on which port is used by the HBA to connect to the fabric, one of the SAN switches receives the request and sends it to the storage processor, which sends it on to the storage device.

5 Market Drivers for SANs: The limitations in speed, distance, and connectivity of SCSI technology prompted the search for an alternative method to access storage devices. The need for LAN-free backups and data sharing started the initial move toward SAN technology. These necessities and the desire to keep all data on-line and accessible 24 hours a day to an increasingly global and/or Internet-based user population are driving current adoption. SAN Management: There are two basic methods for SAN management. SNMP (Simple Network Management Protocol): SNMP is based on TCP/IP and offers basic alert management. This allows a node to alert the management system of failures (drive, fan, power.). However SNMP does not offer proactive management and lacks security. Proprietary Management Protocol: The second way to manage a SAN is to use a proprietary management protocol. There are a number of manufacturers who provide SAN management software. In either case to run management software typically requires a separate terminal (such as an NT server) connected to the SAN. This enables additional capabilities, such as zoning (security), mapping, masking, as well as backup and restore and fault management. Benefits of the SAN : The primary benefits of a SAN are: Availability: A single copy of data is accessible to any and all hosts via multiple paths. Reliability: Dependable data transportation ensures a low error rate, and an ability to recover from failures is provided. Scalability: Servers and storage devices may be added independently of one another, and do not depend on proprietary systems. Performance: Fibre Channel (the standard method for SAN interconnectivity) has a 100MB/sec bandwidth and low overhead, and it separates storage and network I/O. Manageability: Emerging software and standards for both FC-AL and Fibre Channel fabric allow single centralized management and proactive error detection and correction.

6 Return on Information Management: Due to increased redundancy and superior manageability, as well as the ability to add storage and servers independently of one another SANs provide a lower cost of ownership and a Higher Return On Information Management (ROIM). SAN using iscsi: The Small Computer Systems Interface (SCSI) is a popular family of protocols for communicating with I/O devices, especially storage devices. iscsi= Internet SCSI = SCSI over TCP/IP send SCSI commands over an IP network The iscsiprotocol enables universal access to storage devices and storage-area networks (SANs) over standard Ethernet-based TCP/IP networks. iscsimaintains the SCSI notion of an Initiator and Target device iscsiremoves the traditional bus structure of SCSI and maps SCSI over a network iscsisession Types: iscsihas two (2) Session types Discovery Normal Each Session has two (2) Phases Login Contains Security Negotiation and Operational Parameter Negotiation Full Feature Phase Configuration of iscsion Ubuntu: TARGET CONFIGURATION: LioTarget LIOTarget is available in Linux kernels 3.1 and higher. Install the Liotarget packages: # apt-get install targetcli pythonurwid Liotarget is controlled using the targetcli command line utility.

7 Configuration Commands: > targetcli >cd backstores/fileio /backstores/fileio> help create(for help) /backstores/fileio> create lun0 /root/iscsilun0 2g (create 2GB file backed LUN) Now the LUN is created. Next we ll set up the target so client systems can access the storage. /backstores/fileio/lun0> cd /iscsi /iscsi> create(create iqnand target port group) /iscsi/iqn.20...a672ba1/tpgt1> set attribute authentication=0(turn off chap auth) /iscsi/iqn.20...a672ba1/tpgt1> cd luns /iscsi/iqn.20...a1/tpgt1/luns> create/backstores/fileio/lun0(create the target LUN) /iscsi/iqn.20...gt1/luns/lun0> cd../../portals /iscsi/iqn.20...tpgt1/portals> create IP Address of machine (eg ) Register initiator -this IQN is the IQN of the initiator -do this for each initiator that will access the target /iscsi/iqn :3260> cd../../acls /iscsi/iqn.20...a1/tpgt1/acls> create iqn com.redhat:f5b312caf756 /> saveconfig (SAVE the configuration!) /> exit

8 INITIATOR CONFIGURATION: iscsi Initiator Install To configure Ubuntu Server as an iscsi initiator install the open-iscsipackage. In a terminal enter: sudo apt-get install open-iscsi iscsi Initiator Configuration Once the open-iscsi package is installed, edit /etc/iscsi/iscsid.conf changing the following: node.startup= automatic You can check which targets are available by using the iscsiadmutility. Enter the following in a terminal: sudo iscsiadm m discovery t st -p m: determines the mode that iscsiadm executes in. -t: specifies the type of discovery. -p: option indicates the target IP address. If the target is available you should see output similar to the following: :3260,1 iqn com.emc:sl7b The iqn number and IP address above will vary depending on your hardware. Login to the iscsi node: sudo iscsiadm m node login Check to make sure that the new disk has been detected using dmesg: dmesg grepsd

9 Formatting disk: Next, create a partition, format the file system, and mount the new iscsi disk. In a terminal enter: sudo fdisk /dev/sdb n p enter w Now format the file system and mount it to /srv as an example: sudo mkfs.ext4 /dev/sdb1 sudo mount /dev/sdb1 /srv Finally, add an entry to /etc/fstab to mount the iscsi drive during boot: /dev/sdb1 /srvext4 defaults,auto,_netdev 0 0 Reboot Target machine Conclusion: Thus we have implemented and configuration SAN in local Area Network using Liotarget (storage management soft) and iscsi Protocol.