HP StorageWorks SAN Virtualization Services Platform Best Practices Guide (5697-0935, May 2011)

4 Setup virtual disk
The setup virtual disk contains the SVSP metadata. It is accessed by the VSM servers when the
SVSP configuration changes, and must be configured as a high performance and highly available
virtual disk. Configurations with snapshots, mirrors, and thin provisioned virtual disks generate the
most demand for setup virtual disk access. Typically, the larger the environment, the more frequently
the VSM server needs to update the setup virtual disk.
For high availability, the setup virtual disk is configured as a synchronous mirror with 3 to 5 copies
(called tasks in the SVSP terminology). When initially configuring setup virtual disks, consider the
following:
• Setup virtual disk copies must be created from similar performing storage. A high performance
RAID1 LU is required.
• The arrays containing the setup virtual disk copies should not be at or near maximum acceptable
performance limits. Sustained I/O response times to the setup virtual disks should be below
20 ms. The VSM will log a warning if the response time exceeds 20 ms. Use the appropriate
array-based monitor tools to evaluate the array performance.
• Each setup virtual disk copy must be configured so that it is not in the same array failure
domain as any other setup virtual disk copy. Ideally, place setup virtual disk copies on multiple
arrays.
• At least one setup virtual disks must be on an EVA or MSA. This is required to ensure that HP
can troubleshoot problems and verify correct SVSP operation.
CAUTION: When creating a setup virtual disk, only one VSM must be connected to the fabric.
After the setup virtual disk is created, connect the other VSM to the fabric.
All writes to setup virtual disks are mirrored, and therefore the slowest performing virtual disk will
determine when the write is acknowledged. If a single array is all that is available, create the three
setup virtual disks with as much fault tolerance as possible.
TIP: When naming setup virtual disks, ensure that the naming indicates that these virtual disks
are critical to system operation. You may want to edit the comment field for each setup virtual disk
to further express how critical this volume is for normal SVSP operation.
Protecting the setup virtual disk
The SVSP auto-backup function provides additional protection for the SVSP metadata by
automatically creating copies. On a daily basis, the active VSM server copies a backup of the
configuration database (compressed file) into the backup folder residing on the setup virtual disk
itself. On an hourly basis (by default), the active VSM runs an automatic backup of the setup
configuration, which is then stored on the VSM internal hard drive (a RAID 1 set) at C:\Program
Files\Hewlett-Packard\SVSP\Core\Backup. The default backup interval of 60 minutes
can be changed by the administrator, allowing backup schedules to be in minutes, hours, days or
weeks. In the unlikely event of a damaged configuration database, these backup copies can be
used by support engineers for database recovery.
IMPORTANT: HP recommends that you include the backup directory on both VSM servers in your
backup routine.
Creating additional synchronous mirrors of the setup virtual disks
1. In the SVSP GUI, navigate to the Sync Mirror Groups entity. Find the synchronous mirror group
for your setup virtual disk.
Protecting the setup virtual disk 21