Specifications

www.ibm.com/support/techdocs 38

Summary of Best Practices for Storage Area Networks

1) An environmental dependencies checklist should be created and used. As an

example; if upgrading an HBA driver on a server, what are the implications for

other server utilities and hardware (such as multipathing driver, HBA firmware,

etc.) and will support be maintained attaching to another device. These types of

questions must be answered prior to upgrading code on any of the devices.

2) IBM recommends that a proactive code maintenance schedule be put into place

for all devices. While being sensitive to the fact that there is a business to be run

the chances of running into “known issues” increases substantially when running

significantly older code versions. This condition becomes more likely if the entire

environment is not addressed in a systematic manner.

3) IBM Support recommends maintenance of the disk subsystem twice per year.

Reviews for newer releases should be performed more frequently. Please note

that many of the code updates may not be "bug" fixes, but still include

improvements in error correction and diagnostics.

4) Before any “non-disruptive” or “concurrent” upgrade, it is imperative to verify that

hosts have all paths to external disk storage available. If, for whatever reason, a

particular host has lost a significant number of its storage connections, that host

is likely to have major issues during an upgrade.

5) Perform regular inspections of the error logs from critical devices in the SAN

environment. Open a trouble ticket with the appropriate support group on any

suspicious pattern of events that cannot be unexplained.

6) When performing updates to switches within a high availability environment, wait

a minimum of 1 to 2 days before making similar code upgrades in redundant

fabrics.

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