Cluster Shared Volume Effective Virtual Machine Migration. Mohammed Yasser A K Dell Windows OS Engineering

Transcription

1 Cluster Shared Volume Effective Virtual Machine Migration Mohammed Yasser A K Dell Windows OS Engineering

2 Table of Contents Overview What is CSV? Benefits of CSV Requirements Hardware Requirements Software Creating a CSV Creating and Configuring Virtual Disks on storage array Create and Manage a Cluster using Failover Cluster Manager Enabling Cluster Shared Volume Creating Virtual Machines on CSV Hyper V Manager Settings when creating a VM on CSV Configure Virtual Machines Service on the Cluster Virtual Machine Service Configuration Live Migration Quick Migration Known Issues of Live and Quick Migration Tools and References

3 DISCLAIMER THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL INACCURACIES. THE CONTENT OF THIS WHITE PAPER ARE PROVIDED AS IS, WITH NO WARRANTIES, EXPRESS OR IMPLIED. DELL EXPRESSLY DISCLAIMS ANY WARRANTIES OF MERCHANTABILITY. UNDER NO CIRCUMSTANCES, INCLUDING, BUT NOT LIMITED TO, NEGLIGENCE, SHALL DELL BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING, BUT NOT LIMITED TO, LOSS OF DATA OR PROFIT, ARISING OUT OF THE USE, OR THE INABILITY TO USE, THE INFORMATION, EVEN IF DELL OR A DELL AUTHORIZED REPRESENTATIVE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. AT THE TIME OF WRITING THIS PAPER, WINDOWS SERVER 2008 R2 AND WINDOWS 7 ARE BETA PRODUCTS. THE FEATURES AND FUNCTIONALITY OF THESE PRODUCTS AS DESCRIBED IN THIS PAPER MAY CHANGE IN THE FUTURE Dell Inc. All rights reserved. Trademarks used in this text: Dell, PowerEdge, EqualLogic and PowerVault are trademarks of Dell, Inc.; Microsoft, Windows Server, Hyper V, and Windows are registered trademarks of Microsoft Corporation. Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. Dell Inc. disclaims any proprietary interest in trademarks and trade names other than its own. March 2009

4 Overview What is CSV? CSV Definition: a) Windows 2008 R2 s CSVs are shared disks in available storage (LUN) that is visible and accessible to all nodes. b) These shared disks appear as folders in %systemroot%\clusterstorage folder. c) Each volume is labeled Volume1, Volume2 and so on. Limitations in a non-csv setup: a) Export and Import of Virtual Machines is slow and is not automated b) A VM cannot be moved from one host to another without interrupting services running inside the VM. c) No failover modes to ensure availability of Virtual Machines in an event of failed Network Link, IO or Virtualization Hosts. d) In a SAN setup, each disk or LUN is owned by a single node at any point in time, and only that node can perform I/O to it leading to a complex setup NTFS Reason for the above limitations: a) NTFS is not a clustered file system and concurrent access from systems to a NTFS volume is not allowed. b) In a failover cluster, only one node is active for a service/application, and the LUN containing pertinent data is owned by that active node. c) If a service/application has to be moved from one node to another, the volume has to unmounted and remounted to the new active node which would cause downtime. d) This was the only blocking factor for Live Migration feature to work on Microsoft Hyper-V

5 Fig:1 NTFS Volume Access Benefits of CSV How will Cluster Shared Volume help? a) Virtual Machines are stored onto a subfolder of one of the Volumes. b) The great feature of CSV is that all nodes in the cluster can access the content of a CSV concurrently. c) Each VM is placed in its own sub-folder of a volume which in turn enables Live Migration to work efficiently. How is CSV managed and used? a) For each CSV, one node in the cluster acts as the MAIN/COORDINATOR node. b) All nodes trying to write metadata to a CSV send the metadata updates to this main node for the volume. c) All nodes in the cluster can write normal block level information to the volume directly which is the majority of write activity. d) CSV is actually implemented via the CSVFilter.sys file system mini-filter driver which is responsible for the interception of the NTFS metadata requests and all I/O requests in the event a node loses communication with the target volume. e) A node can ask the coordinator to perform all its I/O if it can no longer communicate with the target volume. Requirements Hardware CPU and Memory requirement a) Processors should support Virtualization Technology (Intel VT or AMD-V) b) Do not mix processors from different vendors, based on different family from the same vendor, difference in number of cores and features.

6 c) Live and Quick Migration might fail when trying to migrate from newer family of a specific processor vendor to older version d) Have matching hardware components for best cluster performance e) Make sure all nodes have enough spare memory to take control of another VM when its parent node fails Storage Requirement: a) Make sure the SAN storage array is compatible to Windows 2008 R2 Clustering Service (Refer to Microsoft website for more details on storage compatibility This is to ensure the miniport driver used for the storage will work with Microsoft Storport storage driver) b) Storage Arrays are configured using its respective management software like MDSM or Navisphere Utility. Test for their access from disk management before proceeding with cluster creation. c) Storage disks that are going to be part of CSV should not be a boot or system volume d) Supported storage interfaces include iscsi, FC and SAS For more details on configuring SAN storage arrays from Dell refer to links below, a) iscsi - MD3000i Click here, EMC Storage Click here, Dell EqualLogic Storage Click here b) FC Click here c) SAS Click here Network Requirement a) Have separate network card for storage (iscsi) and network communication b) SAS setup would have limitations to the number of nodes in a cluster Requirements Software CSV Requirement: a) Nodes that will be part of the cluster should be running the latest and same build of Windows Server 2008 R2 Cluster Requirement: a) Do not mix Full and Server Core Edition (Standard Edition does not support Failover Clustering) b) Make sure all nodes are configured to connect to a domain controller and a shared storage (Only FC, SAS and iscsi is supported from Microsoft) c) Make sure the entire Cluster is validated with no errors d) All nodes should have Failover Clustering Feature and Hyper-V Manager Role installed

7 Fig:2 Complete Hardware Setup

8 Creating a CSV Creating and Configuring Virtual Disks on storage array Storage Management Software/Utility: a) Each Storage array vendor provides a management software or utility that enables administrators to create and configure virtual disks from a management station b) Make sure the firmware on the storage array is upto date to ensure compatibility with Windows Server 2008 R2 c) Storage Arrays would also require administrators to install host drivers on each node before proceeding d) In iscsi and FC interfaces, host to virtual disk mapping has to be done using this utility. For more details, refer to the storage array manual e) iscsi storage would need iscsi initiator usage on all hosts to get access f) Use Disk Management within the Operating System to ensure the disks are listed, initialized and in online state g) Create partitions and format it with NTFS Create and Manage a Cluster using Failover Cluster Manager Failover Cluster Manager: a) This feature in Windows Server 2008 onwards will help administrators build redundancy of services and applications on their network and eliminate single points of failure. b) This helps reduce downtime, guard against data loss, and reduce total cost of ownership. c) The feature is not installed by default. It has to be added using Server Manager on all nodes that will be part of the Cluster

9 Creating a Cluster: a) Open Failover Cluster Manager through Administrative Tools from on one of the Nodes to Create and Manage the Cluster b) Click on Create a cluster and it will take the administrator through below steps Select servers (Nodes) that will be part of the cluster

10 The wizard would give warnings if the nodes do not meet the requirements of being part of the cluster. Some warnings include; 1. The node is already part of another Cluster 2. OS types (Full and Core) do not match 3. Failover Clustering service is not added on the node

11 4. Node is not configured to the domain 5. Node is not available or cannot be reached The wizard will prompt the user to run the Cluster Validation Wizard that will test the complete setup including Network, SAN and Node Configurations

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13 c) Review the Cluster Validation Report Any errors on the wizard will block the creation of the Cluster Warnings would still allow me to create a cluster but might impact different failover levels on the cluster d) Manage your cluster Enabling Cluster Shared Volume Enabling Cluster Shared Volume and Adding disk to it a) Refer to figure above where it shows on how to Enable CSV on a Cluster in Failover Cluster Manager. b) Add available storage to the CSV using the option of Add Storage. There should be enough available storage to be added to the CSV. You cannot add storage assigned for Disk Quorum Settings

14 c) Check Disk Management on all nodes and you would see the state changed to Reserved d) On Failover Cluster Manager, check for the current owner of the CSV. This is the Active/Coordinator Node I was referring to in the beginning of the article

15 Creating Virtual Machines on CSV Hyper V Manager Settings when creating a VM on CSV Node Configuration: a) Make sure Hyper-V Role is added on all the Nodes using Server Manager b) Name for Virtual Network Switch on all Nodes should be the same Virtual Machine Configuration: a) If pass-through disks are configured for a specific VM on a node, make sure the disk is on the same network as other nodes b) Make sure Integration Components are installed on all the guest Operating Systems

16 c) Mapped network drives and Image files should be on the same network as other nodes d) Virtual Machine Configuration Settings and respective VHDs to be stored on the C:\ClusterStorage\Volume path

17 e) Make sure Remote Desktop is enabled on all the Virtual Machines for purpose of testing Live Migration f) Test for Virtual Machine functionality through Remote Desktop from another client Configure Virtual Machine Service on the Cluster Virtual Machine Service Configuration Prerequisites: a) Before configuring Virtual Machine Service to the cluster, make sure the above steps were considered while creating the Virtual Machine b) Turn off all the virtual machines that you intend to add to the cluster

18 Adding Virtual Machine Service: a) Click on Configure a Service or Application under the cluster you had created b) Select Virtual Machine and Click on Next c) A small validation check is performed in the background to check if all the nodes on the cluster have Hyper-V Role added and they share the same Hypervisor version

19 d) If VMs are in the running state, the wizard will display an error as below; e) It will list all virtual machines on the cluster and prompt the user to select f) Once selected, it will validate every virtual machine and generate a report

20 g) Report would have warnings or errors if any of the steps mentioned above for VM creation wasn t followed Virtual Machine Summary and Ownership Details: a) Each Virtual Machine Properties will provide settings for configuring Failover and setting preferred owners

21 b) Virtual Machines can be managed directly from the Failover Cluster Manager c) Administrators will also have the option to manually perform Live or Quick Migration of Virtual Machines if a planned downtime is set for any node

22 Live Migration Definition: a) This is a process that can be initiated by user or be automatic in event of failure wherein the VM state and settings are migrated from one node to other b) Users or Clients accessing the VM will still be having access to the VM during this process c) Slower than Quick Migration but is seamless Steps Involved: a) Scenario: The complete hardware and VM setup is shown as below with three VMs being hosted by Node 1 on the Cluster.

23 b) Step 1: For migrating VM2 hosted by Node1 to Node2, the process first starts of with creating and transferring a full memory copy of the current VM state c) Step 2: After this, Dirty pages of memory that include the current changes/process on VM starts getting copied

24 d) Step 3: Cluster Manager should show the Migration to be complete and the respective VM host ownership would be changed to Node 2 During all of the above, the Remote Client/User has still access to the VM and applications on it without any interruption. Quick Migration Definition: a) This is a process that can be initiate by user wherein the VM goes into a Saved state b) Users or Clients accessing the VM will temporarily lose access to the VM till the migration is complete c) Much faster than Live Migration and best suited when the node that is hosting the VM has a planned downtime or when migration was planned

25 Known Issues of Live and Quick Migration Error 1: VM Migration between Intel and AMD Error Message: Reason: Working as designed Workaround: Do an Export and Import of Virtual Machine (Move VMs through Failover Cluster Manager) instead of Quick and Live Migration Error 2: VM Migration between different families of same processor vendor of different families may fail Reason: Working as designed Workaround: Enable Migration through processors where features do not match on the Virtual Machine Processor Setting. Please note this process is not reversible.

26 Tools and References