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

Additional VMware parameters
• ESX/ESXi: VMFS Filesystem Blocksize (1=Default, 2,4,8 MB)— 8 MB is recommended in
order to be able to create VMDKs with a size up to 2 TB (can be important in some
environments).
• ESX/ESXi configuration/advanced parameters:
Disk.UseDeviceReset: 0 (where default is 1)◦
◦ Disk.UseLunReset: 1 (default in ESX/ESXi 4.1 is already 1, so no change is required)
• In ESX/ESXi, do not enable Adaptive queue depth algorithm as stated in http://
kb.vmware.com/kb/1008113. This will not produce the desired effect because SVSP does
not pass through the queue full or busy from the array and does not generate SCSI status
because it is not a target.
• In ESX/ESXi 4.1, VAAI support is not available for SVSP.
Cluster bit in HP-UX/Linux Serviceguard
If virtual disks are presented through the DPMs to Linux or HP-UX without Serviceguard, do not set
the cluster bit, as this will force the DPMs to abort pending writes after a period of time. The cluster
bit is settable on a per-volume basis for SVSP LUNs. From the Serviceguard perspective, I/Os to
all shared volumes used in the cluster need the cluster bit set for Linux and HP-UX. If the cluster bit
is not set, the result could be data corruption. The cluster bit should not be set on volumes presented
outside of the Serviceguard cluster. If the cluster bit is set, and you want to clear the bit:
1. Stop the applications and unmount the virtual disks.
2. Remove permissions to all virtual disks to the host (or cluster) to be changed. Make note the
LU numbers for later reuse.
3. Disable the cluster bit in the UDH definition.
4. Add permissions to all virtual disks previously mapped to the host using the same LU numbers.
5. Rescan for LUNs on the host.
6. Mount the virtual disks and restart the applications.
If the bit is disabled and you wish to enable it, follow the procedure and simply enable the cluster
bit in step 3.
Windows
SQL/TempDB
The SQL-TempDB is created with SQL-startup and deleted with SQL-shutdown. SQL contacts the
SQL TempDB for special commands (index, queries, and so on). It is placed in the same directory
where SQL stores normal databases. Compare with this site to specifically optimize performance:
http://msdn.microsoft.com/en-us/library/ms175527.aspx
Linux
The preferred multipath solution for SVSP with Linux hosts is to use the native Device Mapper
Multipath solution. Contact HP Services for the latest parameters for SVSP which must be entered
in the host's multipath.conf file.
36 Hosts