Originally posted by: diskdur

hi

I have a question concerning the activation of mpio round robin on hdisks.
when hdisks are inside a vg that is varyied on, we have to use the "-P" option of the chdev command.
the problem is that, as soon as the chdev command is issued, the lsattr command report that round robin is enabled.
And this is actually wrong until the reboot.

Is there any way to query aix for current multipathing algorithm ?

There is a kind of workaround ( iostat -d -m ), and check where go the IO... but I would prefer a system command.

Any idea ?

Thanks

dd
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Originally posted by: Renaud

As far as I now, You can't change the algorthym when the disk is used.
With -P flag you have to reboot, to change this value.
But if you are able to exclude your pv from a VG, do a rmdev -l hdiskX, run chdev -l hdiskx -attr .... , run mkdev -l hdiskx. Once the mkdev is ran the algorythm is changed.

With nmon you can see if I/O are balanced between yours adapters.
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Originally posted by: brunotm

echo scsidisk hdiskXX|kdb|egrep "algorithm|reserve_lock"
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Originally posted by: brunotm

This will work in most cases. Compare the values between a known to be changed (without -P flag in chdev) and one with the default value (fail_over)
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