HP StorageWorks X5500 Network Storage Gateway for Linux setup guide (AP811-96003, October 2009)

IMPORTANT:
If the cluster configuration includes an HP Fibre Channel Virtual Connect Module, the guideline
above must be implemented. If this is not done, the cluster can experience excessive timeouts and
a loss of stability.
• The Fibre Channel switches managed by the cluster must be from the same vendor. Switches that
will not be managed by HP X5500 Storage Gateway for Linux can be from other vendors only if
all of the vendors have approved the configuration.
• With fabric fencing, if the servers are connected to switches in multiple fabrics, the physical ports
on each switch must be assigned to unique domain IDs. A different domain ID must be used on
each fabric (any given domain ID can exist on only one fabric in the SAN). For example, if a
server is connected to two switches that are not in the same fabric, switch1 could use domain ID
6 and switch2 could use domain ID 7. Domain ID 6 must not exist on the fabric containing switch2
and domain ID 7 must not exist on the fabric containing switch1.
• To eliminate single points of failure, configure the SAN to use multipath I/O. See the HP Storage-
Works X5500 Network Storage Gateway File Serving Software administration guide for some
sample cluster configurations that include this feature.
• Disk Power Management must be disabled on any Windows systems that have access to the SAN
storage.
NOTE:
You can attach a cluster server to other SANs that are not under HP X5500 Storage Gateway for
Linux control. These SANs can include tape drives and non-PSFS filesystems. You can use Linux utilities
or other applications to access these devices and filesystems.
I/O scheduler policies
The Linux I/O schedulers (also called elevators) attempt to sort and issue disk I/O requests according
to specific priority policies. Testing has shown that the deadline policy results in the best performance
for the PSFS filesystem.
The deadline policy is the default in the SLES10 kernel.
For best performance, HP recommends that you do not change the I/O scheduler policy.
HP StorageWorks X5500 Network Storage Gateway for Linux setup guide 7