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values to verify good I/Oon a lun

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TALVASSON
Frequent Advisor

values to verify good I/Oon a lun

Hello

I have multiple LUN on my LEFTHAND P4000 san

 

What is the common values to I/O latency read and I/O wrtite for a lun?

 

and is there another statistic to manage in orfer to verify the good health of the san

 

thanks a lot

3 REPLIES
oikjn
Honored Contributor

Re: values to verify good I/Oon a lun

guess it all depends on what disks are feeding the P4000s.

 

I think the general rule is to have a que of 2 or fewer per 15k SAS disk, 1.5 or fewer per 10k SAS and 1 per 7.2k SAS/SATA.

 

Letency depends on the disk RPM too.  Not knowing anything about your disks, I would say that if you see over 10ms latency you are seeing a performance problem.

TALVASSON
Frequent Advisor

Re: values to verify good I/Oon a lun

sorry for the missing informations

i have 2 nodes

Each node had 8 disk SAS 15K

 

escuse me i didn't well understand what you mean by:

I think the general rule is to have a que of 2 or fewer per 15k SAS disk

 

can you explain in other termes ?

 

thanks a lot

nicolas

oikjn
Honored Contributor
Solution

Re: values to verify good I/Oon a lun

with 16 total 15k SAS disks, your max IO que should be 30.  If you see a que higher than 30 you are beyond the limit of your disk capacity.