HP VMA SAN Gateway for VMA-series Memory Arrays Release Notes - December 2012

Use the following table to determine appropriate TPCC settings with HP-UX 11i v3 for your

environment:

Table 3. HP-UX 11i v3 TPCC queue depth values.

IF THEN TPCC Settin

I/Os are 4KB aligned and < 256KB 1024 / number of servers*

I/Os are 4KB aligned and > 256KB 512 / number of servers*

I/Os are NON-4KB aligned and < 256KB 512 / number of servers*

I/Os are NON-4KB aligned and > 256KB 256 / number of servers*

* where servers can be a whole physical server or a partition.

Linux

The Linux distros RHEL 5.8, 6.2, SLES 11 SP2 and OL 5.8 have been validated on the DL980 and

RHEL 6.2, OL 5.8 have been validated on DL580 G7 server and BL680 Blade Server with the HP

VMA SAN Gateway software OE version G5.5.1 and connected VMA-series Memory Arrays using

firmware version A5.1.4. Additional limitations and considerations for Linux environments are shared

in the following subsections.

Recommended Multipath Settings

For Linux environments, it is recommended to change from the default settings for multipathing. For

heavily loaded I/O environments, such as with the VMA SAN Gateway, it has proven to be more

efficient to use the ‘tur’ checker method instead of the ‘readsector0’ or ‘directio’ alternatives to check

the health of lunpaths. An example multipath setting would be:

devices {

device {

vendor "VIOLIN"

product "SAN ARRAY"

path_grouping_policy group_by_serial

path_checker tur

# uncomment the corresponding getuid_callout for your OS

# Ubuntu getuid_callout "/lib/udev/scsi_id -p 0x83 -g -u -s /block/%n"

# RHEL5/OL5 getuid_callout "/sbin/scsi_id -p 0x80 -g -u -s /block/%n"

# RHEL6/OL6 getuid_callout "/sbin/scsi_id --whitelisted --replace-whitespace --

page=0x80 --device=/dev/%n"

# SLES11 getuid_callout "/lib/udev/scsi_id --page=0x83 --whitelisted --replace-

whitespace --device=/dev/%n"

path_selector "round-robin 0"

failback immediate

rr_weight uniform

no_path_retry 6

# For RHEL6.2 or other newer kernels (see man multipath.conf), change to

rr_min_io_rq

rr_min_io 4

fast_io_fail_tmo 5

dev_loss_tmo 30

}

The ‘rr_min_io’ value denotes the minimum number of I/O operations to send down the current

lunpath before selecting the next lunpath. A lower value than typically used with standard rotational

media storage array controllers has proven better to keep all lunpaths busy. This value could be

further tuned for your specific environment based on workload and number of lunpaths.