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Multipath with different speed.
Hi,
I have a server that has 4 hba's and two of them are set to 4gig while the other two are 2gig.
There are two fabric, and each fabric has 1 2gig and 1 4gig hba. I am seeing a lot of IO waits on the server during some batch jobs (all 4 paths). powerpath shows small amount of (less than 5) qe'd IO on the 4gig path.
Is this because of the different port speed?
Jay
Quincy561
1.3K Posts
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November 11th, 2010 12:00
How is the response time? IO wait isn't generally a bad thing as long as you have reasonably good response times.
Boom1
131 Posts
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November 11th, 2010 12:00
you have powerpath here so your multipathing tools is not working only on # of IO. it may consider response time.
But server is not doing balanced IO on storage FA port because of different port speed
what is port utilization and what is total IO on all 4 path?
Nollaig1
137 Posts
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November 15th, 2010 03:00
Hello JayPat,
Also bear in mind that the queued I/O value is cumulative. So, if you see 5 I/O errors, these are errors on the link since the last reboot.
If the errors increase during/after your batch load, it would indicate pressure on the paths.
Also, the powerpath policy you use, will dictate the loadbalancing policy.
Investigating the host log files, will indicate when an issue has been seen on the link.
Hope this helps,
Nollaig