Originally posted by: ThomasJO

Here's my situation. I have setup my Storage drives to use MPIO, no_reserve and the round_robin algorithm. And it's working very well for us. However, whenever we add drives to the LPARs we have to remember to manually set the new drives to no_reserve and round_robin. Many times this step is forgotten and then there are drives that are not set to "load balance" their I/O. I seem to recall reading somewhere that there is a way (i.e. not manually manipulating the ODM) to set the default settings so new drives would already come in with the no_reserve and round_robin already set. However, I can not find / remember how to do it.

Am I remembering this correctly? If so, how do I do it?

Any help will be appreciated. Thanks.

Originally posted by: j.gann

replace the default value in the PdAt ODM Class entry matching the uniquetype of your disk device and the attribute name of the desired attribute (reserve_policy ... whatever)

odmget, odmchange commands should do

Joachim Gann

Originally posted by: The_Doctor

I think your original question has already been addressed.... here's an alternative:

SDDPCM may not be for everyone, BUT IF SDDPCM fits in your environment.... I think you'll like the default settings of "no_reserve" & "load_balance". Works for both VIO Servers and AIX Client LPARs.

You didn't mention the disk sub-system(s) you were using so you'll need to decide if SDDPCM is a fit for you.

Originally posted by: ThomasJO

Thanks guys.

It dawned upon me this morning that what I was thinking of was an EMC supplied script (We have EMC VMAX storage). When I looked through the script I saw it is doing an odmget and an odmchange in the background.

symm_fcp_mpio_change_no_reserve()
{
print "************************"
print "* Status BEFORE update *"
print "************************\n"
odmget -q'uniquetype LIKE disk/fcp/MSYMM* and attribute=reserve_policy' PdAt | egrep "uniquetype|deflt"

odmchange -o PdAt -q"uniquetype LIKE disk/fcp/MSYMM* and attribute=reserve_policy" << EOF

PdAt:
deflt = "no_reserve"
EOF
print " ODM updates - reserve_policy=no_reserve - installed sucessfully \n"

print "************************"
print "* Status AFTER update *"
print "************************\n"
odmget -q'uniquetype LIKE disk/fcp/MSYMM* and attribute=reserve_policy' PdAt | egrep "uniquetype|deflt"
print "\n
}
Looks like this is probably the best way to handle the situation.