HP StoreVirtual Storage Multi-Site Configuration Guide Abstract This guide contains detailed instructions for designing and implementing the Multi-Site SAN features of the LeftHand OS. The Multi-Site SAN features enable you to synchronously and automatically mirror data between geographic sites. Topics include designs for network configurations and instructions about implementing the network designs. The intended audience is system administrators who manage HP StoreVirtual Storage solutions.
© Copyright 2009, 2013 Hewlett-Packard Development Company, L.P. Confidential computer software. Valid license from HP required for possession, use or copying. Consistent with FAR 12.211 and 12.212, Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under vendor's standard commercial license. The information contained herein is subject to change without notice.
Contents 1 Designing a Multi-Site SAN.........................................................................5 Designing the network for the Multi-Site SAN...............................................................................5 Best practices for implementing the Multi-Site SAN network.......................................................5 Common Multi-Site SAN network designs................................................................................
To add capacity............................................................................................................28 Removing storage systems from a Multi-Site cluster.......................................................................29 To remove the storage systems from the site...........................................................................29 Removing servers from a site....................................................................................................
1 Designing a Multi-Site SAN The HP StoreVirtual Multi-Site SAN features enable you to synchronously mirror data between sites automatically. You create a Multi-Site SAN by configuring equal numbers of storage systems into sites in the software.
• Low round-trip latency—In order to not impact disk I/O to the application server, the round-trip latency between the sites must be no more than 2 ms. • Redundant links—Have multiple physical connections (media) between the sites for redundancy. The network should be configured so that a link failure does not cause the Multi-Site SAN to go offline. • Assign servers to sites—Avoid high-latency connections by assigning application servers to the site where the server is located.
Sample recommended network configurations for Multi-Site SANs This section provides illustrations of common network configurations for the topologies described in Table 1 (page 6). The clusters and sites can have many more storage systems than are depicted in these illustrations, which focus on the network design. Figure 1 Dual redundant links between two sites 1. Dual redundant GigE links Figure 2 Dual redundant links between two sites with Failover Manager in logical third site 1.
Figure 3 Triangular network with Failover Manager 1. Dual redundant GigE links Figure 4 Hub and spoke network core with redundant links out to each site 1.
Figure 5 Combination full-mesh core with triangular links to all sites 1. Full mesh core network Using multiple subnets IMPORTANT: Best practice is to use a single subnet in most cases. You can use multiple subnets with a Multi-Site SAN. Multiple subnets let you have multiple VIPs, one VIP per subnet. The advantage of using multiple VIPs is that you can connect to a volume without having to leave the local subnet. Alternatively, you can assign an application server to a site.
Figure 6 Multi-Site SAN mapping to subnets, VIPs, and application servers 1. Dual redundant GigE links Connecting volumes to multiple subnets in a Multi-Site SAN using the Microsoft iSCSI initiator Connecting to volumes in a multiple subnet configuration is similar to connecting to volumes in a single-site configuration, with the following important differences: • You must configure all cluster VIPs for discovery, for proper failover/failback configuration of a Multi-Site SAN.
Figure 7 Entering VIPs in a Multi-Site SAN configuration 2. 3. 4. On the Targets tab, select the volume to log on to. Click Log On. Select the Enable multi-path check box if using MPIO. Figure 8 Logging on to volume 5. 6. 7. [Optional] If you want this volume to be available after rebooting, select the Automatically restore... check box. Click Advanced to open the Advanced Settings window. Configure the Advanced Settings as follows: • For Local adaptor, select Microsoft iSCSI initiator.
Figure 9 Target portal value remains Default 8. After setting the values, click OK to close the Advanced Settings dialog. 9. Click OK again to finish logging on. 10. If you want to set the MPIO load balancing policy, see the HP StoreVirtual Storage DSM for MPIO Deployment Guide. 11. If you have multiple NICs, repeat steps 1 through 10 for the additional NICs.
In addition to setting up the Multi-Site clusters for data replication, it is important to set up the SAN managers for quorum correctly to ensure that in the event of a failure the system can be properly recovered. Maintaining quorum can be either an automated process or manually recovered by an Administrator. Table 2 (page 13) summarizes common Multi-Site SAN and manager configurations.
Figure 11 Two physical sites, logical third site: cluster spans two sites, Failover Manager in logical third site 1. Volumes are configured with Network RAID-10 Figure 12 Three physical sites: cluster spans three sites 1.
Figure 13 Two physical sites: cluster spans two sites, one site is the primary site 1. Volumes are configured with Network RAID-10 Best practices for configuring quorum and managers in a Multi-Site SAN environment Configuring the appropriate number of managers in a Multi-Site SAN on the appropriate storage systems is an important part of setting up the Multi-Site SAN for high availability and fault tolerance.
Table 3 Common Multi-Site SAN configurations with recommended managers Multi-Site SAN configuration Manager configuration Two physical sites, one site is primary For four storage systems, run: • Two managers in the primary site • One manager in the secondary site For six storage systems or more, run: Number of managers and number Needed to maintain quorum • Manager count = three Number for quorum = two • Manager count = five Number for quorum = three • Three managers in the primary site • Two managers i
Table 4 Data protection levels and the supported number of sites Data protection level Number of sites supported Network RAID-10 Two Network RAID–10+1 Three NOTE: Two sites are supported, but not considered a best practice configuration. Network RAID–10+2 Two NOTE: Three sites are supported, but are not considered a best practice configuration.
Table 5 Failure conditions and resolutions Failure condition Resolution steps Secondary site offline None. The primary site will continue to operate. Network link between sites fails None. The primary site will continue to operate. Primary site offline 1. If any of the storage systems running managers in the primary site can be brought back online, you should do this first. 2.
Table 6 Alternative Multi-Site SAN configurations (continued) Alternate configuration Description Details be Multi-Site if it is to contain storage systems from different subnets. Using Virtual Manager IMPORTANT: practice. This is not a best The Virtual Manager capability remains in the product (a manual process for recovering quorum). The Virtual Manager is used in two-site configurations, and is not as commonly used as the Failover Manager.
2 Implementing a Multi-Site SAN After you have designed the Multi-Site SAN configuration, you are ready to implement it. Before you begin Install Multi-Site SAN feature keys on the storage systems you are going to use. Register your storage systems. For more information, see “Registering advanced features” in the HP StoreVirtual Storage User Guide for information about registering your storage systems.
Figure 14 Using the management group wizard to create a Multi-Site SAN NOTE: You must have at least one storage system for each site in the Available Systems pool before starting. Creating the management group The first part of the wizard creates the management group, which includes configuring the optimal number of managers for the initial setup.
Creating sites When creating a new site, you first create the site and then assign storage systems to that site: 1. Click New to open the New Site window. 2. Enter a name for the site and an optional description. 3. [Optional] Make the site primary, if appropriate. 4. 5. Click Add in the Site Systems section and then select the storage systems for this site. Click OK when you have finished creating the site.
Figure 16 Viewing the Sites Details tab window Converting an existing SAN to a Multi-Site SAN Plan the conversion according to the criteria described in “Preparing to convert an existing SAN to a Multi-Site SAN” (page 20). Prerequisites • Upgrade all storage systems to LeftHand OS software version 7.0 or later. • Obtain the feature keys for storage systems to be used in the Multi-Site cluster. • Apply the feature keys to the storage systems.
10. Assign one or more VIPs as planned for your site layout, and then click Next. The Create Volume window opens with the Skip Volume Creation box checked. If you want to create a new volume for your Multi-Site cluster, clear the box and fill in the volume information. 11. Click Next to complete the wizard. 12. Verify the settings for the sites you have just configured. 13. Click Close when you finish reviewing the Summary information.
Best practice Install the Failover Manager on a server in a separate physical location from the SAN sites, and then add it as a separate site in the management group. Doing so will prevent loss of quorum in a site failure, regardless of which single site fails. Adding the Failover Manager to the management group and site Adding the Failover Manager to the management group will likely cause the manager configuration to become less than optimal.
Viewing sites in the CMC To view sites in the CMC, select the Sites node in the navigation window. The Sites node is displayed in every management group. Typically, however, the Sites Details tab shows the storage systems as unassigned. The site designation has no effect outside of the Multi-Site SAN configuration. Figure 17 No sites in a standard cluster When there is a Multi-Site cluster in the management group, the Sites Details tab shows the site assignments of the storage systems and servers.
• Sites • Sites (Grouped) Designating a primary site Use the Primary designation when you are using the Multi-Site cluster to maintain a primary site and a second site as a backup site. Designate the site as Primary when you create the site, or you can edit an existing site to make it primary. Only one site can be designated as Primary in a Multi-Site cluster. Make sure that the majority of managers are in the Primary site.
1. 2. Select the Sites node in the navigation window. Select the site you want to delete in the Details tab, right-click, and then select Delete Site. NOTE: If only one site will be left in the cluster, the warning shown in “Deleting a site that contains a storage system causes this warning” (page 28) is displayed. Figure 19 Deleting a site that contains a storage system causes this warning 3. Click OK to delete the site.
Removing storage systems from a Multi-Site cluster Removing storage systems from a Multi-Site cluster affects the capacity of the cluster and the Multi-Site configuration. • Ensure that the capacity remaining after you remove the storage system(s) is sufficient for the data on the volumes. • To maintain the Multi-Site configuration, plan to remove equal numbers of storage systems from each site. To remove the storage systems from the site 1. 2. 3. 4. Select the Sites node in the navigation window.
3 Support and other resources Contacting HP For worldwide technical support information, see the HP support website: http://www.hp.
initiate a fast and accurate resolution, based on your product’s service level. Notifications may be sent to your authorized HP Channel Partner for on-site service, if configured and available in your country. The software is available in two variants: • HP Insight Remote Support Standard: This software supports server and storage devices and is optimized for environments with 1-50 servers.
4 Documentation feedback HP is committed to providing documentation that meets your needs. To help us improve the documentation, send any errors, suggestions, or comments to Documentation Feedback (docsfeedback@hp.com). Include the document title and part number, version number, or the URL when submitting your feedback.
Glossary The following glossary provides definitions of terms used in the LeftHand OS software and the HP StoreVirtual Storage. acting primary volume The remote volume, when it assumes the role of the primary volume in a failover scenario. Active-Passive A type of network bonding which, in the event of a NIC failure, causes the logical interface to use another NIC in the bond until the preferred NIC resumes operation. At that point, data transfer resumes on the preferred NIC.
DSM Device Specific Module. DSM for MPIO The HP StoreVirtual DSM for Microsoft MPIO vendor-specific DSM that interfaces with the Microsoft MPIO framework. failback After failover, the process by which you restore the primary volume and turn the acting primary back into a remote volume. failover The process by which the user transfers operation of the application server over to the remote volume. This can be a manual operation, a scripted operation, or VMware enabled.
MIB Management information base. A database of managed objects accessed by network management protocols. An SNMP MIB is a set of parameters that an SNMP management station can query or set in the SNMP agent of a network device (for example, a router). Multi-Site cluster A cluster of storage that spans multiple sites (up to three).
RAID rebuild rate The rate at which the RAID configuration rebuilds if a disk is replaced. RAID status Condition of RAID on the storage system: • Normal - RAID is synchronized and running. No action is required. • Rebuild - A new disk has been inserted in a drive bay and RAID is currently rebuilding. No action is required. • Degraded - RAID is not functioning properly. Either a disk needs to be replaced or a replacement disk has been inserted in a drive.
site A user-designated location in which storage systems are installed. Multi-Site SAN configurations have multiple sites with storage systems in each site, and each site has its own subnet. A site can be a logical configuration, such as a subnet within the same data center, department, or application. SmartClone volume SmartClone volumes are space-efficient copies of existing volumes or snapshots. They appear as multiple volumes that share a common snapshot, called a clone point.
volume size The size of the virtual device communicated to the operating system and the applications. VSS Provider HP StoreVirtual VSS Provider is the hardware provider that supports the Volume Shadow Copy Service on the HP StoreVirtual Storage. VSS Volume Shadow Copy Service writable space See temporary space.
Index Symbols 2-site configurations primary site designation in, 17 A adding additional capacity to existing sites, 28 site, 27 storage systems to Multi-Site cluster, 28 alternative Multi-Site SAN configurations, 18 application clusters setting up in a Multi-Site SAN environment, 17 application server connecting to Multi-Site SAN, 12 application servers assigning to sites, 6 B benefits of a Multi-Site SAN, 5 best practices failover manager, 6 implementing Multi-Site SAN network, 5 installing Failover Mana
for sites, 26 MPIO and multiple subnets, 12 Multi-Site cluster creating, 21 removing storage systems from, 29 wizard, 23 Multi-Site SAN alternative configurations, 18 common configurations with recommended Failover Manager, 15 common network designs, 6 converting from an existing SAN, 23 implementing, 20 installing, 20 multiple VIPs as feature of, 9 overview, 5 preparing to implement, 20 overview managers, 24 Multi-Site SAN, 5 sites, 25 servers assigning to sites, 6 removing from a site, 29 setting up app
