2011-02-25 12:19 PM
I am looking for the calculation to find out the maximum IOPS that a Disk shelf can provide , Raid type is RAID-DP .
1) is it just Number of disk X IOPS per disk
It should not be right ? we have to consider write penalty for parity and also the Shelf Loop has a limitation of bandwidth (2G/4G)
2) How Size of IO and Type of IO play their part ..
For example : If we consider 50% Read and 50% write IOPS, how much IOPS we will get , and how its is calculated
3) How latency play its part in the calculation .....
I am searching a deatiled calculation that consider these all matrix and provide the IOPS that a Shelf offer ...
Do netapp explains these calclulation somewhere , Any Doc will be gr8 help
Thanks in advanced
2012-06-15 01:12 PM
There are two ways you can approach this:
1) NetApp sizers dealing with different applications / workloads (e.g. Oracle, Exchange, SQL, etc.)
2) rule of thumb sizing, based on average number of IOPS per disk / spindle
The second approach assumes all IOPS are random with the majority of reads. Typical 'rough' figures I've seen are:
- 180-200 IOPS per 15k spindle
- 60-80 IOPS per SATA spindle
(you exclude parity & hot spare drives from calculations)
2014-08-27 01:02 AM
I wrote a article about this subject with how 3140 and 3160 latency levels compare and also how to calculate the theoretical maximum IOps based on type and quantity of hard disk in a RAID-DP based aggregate.
Hope this helps
2015-03-03 04:26 AM
I Just came across this calculation
Raw IOPS = Disk Speed IOPS * Number of disks
Functional IOPS = (Raw IOPS * Write % / RAID Penalty) + (RAW IOPS * Read %)
Note :- For Raid 6 write penalty is 6.
Hope it helps.
2016-08-17 05:57 PM
seeing as most the tech support are clueless with performance analysis I will help the OP out.
Run this command
statistics show-periodic -object disk:raid_group -instance /node1_aggr1/plex0/rg0 -counter read_ops|write_ops -interval 1 -iterations 60
you will need to be in Priveleged Mode - Advanced.
From there you can work out your read/write % and actually work out how to fix it, DO NOT Involve netapp support - they will read off a script and ask for a perfstat then a week later they will say "buy more disk" rather than, oh you have high latency? maybe you need to re-balance the aggregate? or reallocate or add jumbo frames or anything constructive lol.