NL Drives and Raid configuration

afidel · **Joined:** Tue May 07, 2013 1:45 pm **Posts:** 216

Yeah, putting anything with any kind of IOPS requirement on an NL only CPG is a really bad idea. I'd create an AO policy with either 2 or 3 CPG's (depending on how badly you want to keep these VM's off SSD) and do a series of tunevvol to move everything off the NL disks and onto FC and let only the cold blocks fall down to NL. Your current setup is overdriving the NL disks by 300+% so you at least need to triple your NL disk count if you continue doing things the way you are today, and because with added IOPS capacity your IOPS requirement might continue to go up even 3x as many disks might not be enough. Basically you have at least part of your workload that's currently on NL that really needs the IOPS/GB density of FC (if not a bit of SSD) and so putting it on an NL tier is not going to be cost effective as NL disks have poor IOPS/$.

Richard Siemers · **Posted:** Sun Apr 12, 2015 4:18 pm

I'm suspect of NL drives able to push 150 iops. Is that a momentary spike? or sustainable iops count?

When someone says 150 iops, 10k FC/SAS drives come to mind. (per PD)

Architect · **Joined:** Thu Dec 06, 2012 1:25 pm **Posts:** 138

Purely sequential, they can reach those numbers.
It would be almost impossible for random io, agreed.

kk2491 · **Joined:** Fri Dec 05, 2014 6:42 am **Posts:** 169

Schmoog wrote:

Architect is right, a region density report is a good place to start. If there are a lot of vm's residing on nl, it could be a noisy neighbor or two or three.

How many nl disks do you have in the system?

Hi Schmoog,

Sorry for delay, I was on leave.

We have 80 NL drives each having 2TB size.

Also I need assistance in creating the region density report.

Regards,
KK

kk2491 · **Joined:** Fri Dec 05, 2014 6:42 am **Posts:** 169

Richard Siemers wrote:

I'm suspect of NL drives able to push 150 iops. Is that a momentary spike? or sustainable iops count?

When someone says 150 iops, 10k FC/SAS drives come to mind. (per PD)

Hi Richard Sir,

I dont think it is momentory spike. In the OSSA report sent by HP it clearly shows NL drives reaching beyond 150. (Some drives even 170) Even we are wondering.

And also want to know what would be the impact of this?

Also I need help in balancing the chunklets counts across all the 80 NL drives, as I could see chunklets are not evenly distributed.

Regards,
KK

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NL Drives and Raid configuration

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