Comments for vPivot

Comment on Storage Performance Analysis: SingB Case Study by HoosierStorageGuy

HoosierStorageGuy — Sun, 13 May 2012 22:59:45 +0000

Great write up! Very easy to understand for just about anyone. For any customers reading, I’d like to emphasize the point “never hesitate to escalate”. As a former EMC Customer and EMC’er myself, I have seen first hand the willingness to go above and beyond when it comes to helping customers. If you’re having a problem, your vendor(s) need to know about it! If you’re working with a good business partner, they’ll step up and take advantage of tools they have as is shown in this post.

Comment on Storage Performance Analysis: SingB Case Study by drummonds

drummonds — Fri, 11 May 2012 22:32:58 +0000

The example is a bit simplified. One of the things I discovered in this process is the notion of “average array IOPS” lacks a clear definition. In three separate tools we got averages ranging from ~7K, ~10K, ~13.5K. You can derive these numbers based on when the sample occurs, whether averages are done across time slice, across LUN, whether each sample is an average or a peak, etc.

Also remember that the number you’re seeing is a 24-hour average. The problems were occurring during a small portion of the day. I will estimate that this array was at maximum throughput at somewhere between 15-20k IOPS. But with a proper design I think we can get its maximum above 30k. But that will depend on a lot of other factors like IO size, sequentiality, obviously.

Comment on Storage Performance Analysis: SingB Case Study by Andrew Fidel

Andrew Fidel — Fri, 11 May 2012 06:41:03 +0000

Scott,
Is this a very simplified example or is a CX4-480 really falling over at ~6,500 total frontend IOPS?

Comment on Storage Performance Analysis: SingB Case Study by Rohan

Rohan — Fri, 11 May 2012 01:49:51 +0000

Yes – you are referring to the Full Stripe Write operation.

The CLARiiON or VNX in its normal cached operation optimises disk I/O to perform Full-Stripe writes whenever possible. A full-stripe write is somethimes referred to as a Modified RAID-3 (MR3) write.

If the incoming I/O is large enough to fill the RAID-5 stripe and it is aligned to the disk/block boundaries, or the storage processor has accumulated enough write I/Os in write cache, then a full strip write is performed.

Also, depending on the data locality, it is possible to coalese smaller I/O writes into fewer larger writes. It is possible to sequence individual write requests in cache until an entire stripe is full, before writing it to disk. This makes for more efficient use of drives and the back-end bus.

Comment on Storage Performance Analysis: SingB Case Study by Thanga

Thanga — Thu, 10 May 2012 12:50:20 +0000

Good analysis and explanation for VMware and Storage gurus. Well done Scott!

Comment on Storage Performance Analysis: SingB Case Study by iwan 'e1' Rahabok

iwan 'e1' Rahabok — Thu, 10 May 2012 12:33:51 +0000

Thanks Scott for the analysis. Will try my best to attend the meeting on Friday afternoon.

Comment on Storage Performance Analysis: SingB Case Study by PiroNet

PiroNet — Thu, 10 May 2012 07:51:22 +0000

Great post!
Isn’t there RAID5 write optimization mechanism available on CX4-480 series which can outperform RAID10 in certain situation?

Comment on Virtualization Week in Singapore by Iwan

Iwan — Tue, 01 May 2012 12:55:06 +0000

I’m planning an FSI only session. It will be peer discussion so everyone gets to share real world implementation. Perhaps a title like “banking on virtualization”
I’m thinking just 20 pax else it won’t be a discussion if it’s too big. Will do early June. Let’s sync up!

Comment on Microsoft 2.0 by Iwan

Iwan — Tue, 01 May 2012 12:50:04 +0000

I see the same thing. The world post O/P release will be interesting indeed.

Comment on x86 Über Alles by Iwan

Iwan — Tue, 01 May 2012 12:46:14 +0000

I was with a local bank. The server team have a per core pricing from a unix vendor. And it was priced low too. That makes the unix OS doing well in this bank. Yup, I was surprised