Comments on: IBM DS3300 iSCSI Write Performance Solved

By: Mike

Mike — Fri, 13 Jan 2012 04:20:33 +0000

Hi Josh, thanks for a great article. Do you happen to have the url where you downloaded the DS Command Line Interface? Is it a separate download or packaged with something else? I can’t seem to find it anywhere.

By: Mike

Mike — Fri, 13 Jan 2012 00:53:58 +0000

Thanks much for this article Josh. It’s been a big help in monitoring and performance tuning our ds3300. I’m having a hard time finding the command line interface. Do you remember, was it a separate download, or packaged with something else? Do you happen to have the url for the download?

By: Joshua Townsend

Joshua Townsend — Mon, 14 Nov 2011 20:09:53 +0000

There are too many variables to give a fixed answer. It really depends on your workload (read vs. write, random vs. sequential, small vs. big), your multipathing setup, your use of cache, the type of disks you have, the number of disks you have, etc.

By: Alvin

Alvin — Sun, 13 Nov 2011 08:17:47 +0000

What is the maximum read/write speed or IBM DS3300 running at iSCSI connection to host?

By: Panny

Panny — Thu, 22 Sep 2011 03:45:11 +0000

Thankyou for this Joshua, it really helped me!

By: Martin

Martin — Tue, 17 May 2011 14:18:11 +0000

Thanks a lot!!! It worked perfect for me!

By: Vahur

Vahur — Thu, 10 Feb 2011 08:46:17 +0000

Hi,

having the same issue as described on a single controller DS3200 box. Except for the SAS controller, it should be exaclty the same hardware.
However, in my case – all of the performance “tweaking” has no efect what-so-ever. As soon, as there’s a SATA disk (officially supported IBM disks ofcource) inside the unit, the write-performance drops to below 10Mbytes/sec. Unit has been in IBM now for about 2 weeks, and all they could come up with – is: “it seems that the controller of DS3200 is not able to handle SATA disks correcly and there’s nothing to doo about it. With SAS disks and 7200 krpm NL SAS disks it’s working fine”. Guess which disks we have… so beware everybody.

By: cary

cary — Mon, 27 Dec 2010 18:42:48 +0000

New to the IBM DS3200, How do i get to see the settings on my unit? what is the command to show the settings that i would input in the script window?

By: Joshua Townsend

Joshua Townsend — Tue, 23 Nov 2010 22:57:29 +0000

Thanks for the comment, Andrew. You are correct that direct attached is easier, but it does not scale well. Once you get a few ESX/ESXi hosts and want to start doing vMotion, DRS, HA, etc. you have to get into SAN or NAS storage.

By: Andrew

Andrew — Tue, 23 Nov 2010 22:51:47 +0000

Just wanted to say thanks for the Article – seems some of the ‘tuning’ that you suggest certainly helps in the small VMware environment I run. 2 Dell PowerEdge 1950 G3s connected through SAS to MD3000.

For a small environment – it seems that SAS is easier to deal with, not another network to setup, no extra switches and the headaches that go with tuning the iSCSI settings.

By: Joshua Townsend

Joshua Townsend — Wed, 17 Nov 2010 16:52:06 +0000

I am running different subnets for the ports on each controller - Controller A, Port 0 and Controller B, Port 0 should be on one subnet; Port 1 from A & B should on another. Jumbo frames is enabled, although I can't say I saw much of a difference with it. I was using the DS3300 to back my VMware environment, so following suggestions here: http://virtualgeek.typepad.com/virtual_geek/2009/09/a-multivendor-post-on-using-iscsi-with-vmware-vsphere.html and here http://blog.scottlowe.org/2008/04/22/esx-server-ip-storage-and-jumbo-frames/ were very helpful to me as well.

By: Antony

Antony — Wed, 17 Nov 2010 11:04:48 +0000

Hi Joshua, im just wondering, with your config are you running different subnets for each controller, and have you got jumbo frames enabled ? i have been trying to find the best configuration and have managed some pretty high numbers, but im always on the lookout for what everyone else has set the units up like.

Thanks
Ant

By: Joshua Townsend

Joshua Townsend — Mon, 18 Oct 2010 18:31:16 +0000

@WMickey – thanks for the comment. Great to hear that IBM support has found this useful too! I appreciate you taking the time to add some details.

Josh

By: WMickey

WMickey — Mon, 18 Oct 2010 18:23:11 +0000

This Article was very helpful to solve exactly the same problem on my DS3300 single controller storage as write speed turn from 7 Mbps to 60Mbps
Even IBM official support used this article to figure out this issue

I would like to add couple of notes for future readers
The write cache can only be enable if the battery state is in full health
As I experience the same problem with the battery as Joshua (incomplete battery learn cycle error) only after I replace the battery and wait 24 hours to charge it
I was able to run the script successfully

First run:
set allLogicalDrives mirrorCacheEnabled=false

Second run:
set logicalDrive ["lun_name"] writeCacheEnabled=true;

After scrip run setting should look like this

Read cache: Enabled
Write cache: Enabled
Write cache without batteries: Disabled
Write cache with mirroring: Disabled
Flush write cache after (in seconds): 10.00
Dynamic cache read prefetch: Enabled

By: Joshua Townsend

Joshua Townsend — Tue, 12 Oct 2010 17:53:23 +0000

The MD3000i cache configuration is done at the command line, not in the GUI. Check out the CLI guide here: http://support.dell.com/support/edocs/systems/md3000i/en/2ndGen/CLI/HTML/.

By: Nawir

Nawir — Mon, 11 Oct 2010 01:32:40 +0000

Leandro,

I encounter the same problem like you, from esx to copy 500MB take 40s while from windows 2008 only take 5s.
But I can’t find where to disable/enable write cache in MD3000i Storage Array Profile.
In which menu I can find it? Is it in Summary, RAID controller Modules or in Disk Groups.
Please elaborate

thanks

By: Pradeep Goonetillake

Pradeep Goonetillake — Fri, 08 Oct 2010 15:28:53 +0000

Thanks a lot for this article. One of my customer’s had a performance issue when deleting snapshots(using Veeam) on a IBM DS3300. I was pulling my hair out to see why this was happening. He was having a single controller unit. I could fix the problem by disabling the write suspension.

Thanks

Pradeep

By: Shahar

Shahar — Fri, 24 Sep 2010 23:35:42 +0000

Hi Joshua,
Very nice post.
What is your recomendation for a dual controller setup?
I have dual 512MB controllers and I’m getting ~30MBps on average with high latency.
I have 12 disks in raid 6 and ~30 VMs.

Thanks

By: Free SAN Monitor for DS3300, MD3000i and others | VMtoday

Free SAN Monitor for DS3300, MD3000i and others | VMtoday — Fri, 07 May 2010 21:55:12 +0000

[...] of my most popular posts to date had been IBM DS3300 Write Performance Problem Solved. I am pleased to have upgrade my internal environment to an EMC Clariion CX4 array, but still [...]

By: Joshua Townsend

Joshua Townsend — Wed, 05 May 2010 14:46:56 +0000

Leandro – happy to hear this was helpful for you!

-Josh