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Checking num_cmd_elems for VFC adapters with kdb
This entry is
similar in theme to one of my previous posts about verifying your hdisk queue_depth settings with kdb . This time we want to check if an attribute for a Virtual FC (VFC)
adapter has been modified and whether or not AIX has been restarted since the
change. The attribute I’m interested in is num_cmd_elems .
This value is often changed from its default settings, in AIX environments, to improve
I/O performance on SAN attached storage. From
kdb you can identify the VFC
adapters configured on an AIX system using the vfcs... [More]
Tags:  odm -p kdb lsattr chris_gibson num_cmd_elems adapter vfcs aix chdev reboot vfc |
Checking your queue depth with kdb.
Just say you
change the queue_depth on a hdisk
with chdev –P . This updates the devices
ODM information only, not its running configuration. The new value will take
effect next time I reboot the system. So now I have a different queue_depth in the ODM compared to the
devices current running config (in the kernel). What if I
forget that I’ve made this change to the ODM and forget to reboot the system
for many months? Someone complains of an I/O performance issue....I check the
queue_depths and find they appear to be set appropriately... [More]
Tags:  lsattr chris 7.1 chdev queue_depth odm aix -p kdb gibson 6.1 |