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md3000i + md1000 + 15x450Gb 15kSAS = Poor Performance

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md3000i + md1000 + 15x450Gb 15kSAS = Poor Performance

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Morning,

We recently acquired a used md3000i with an md1000 added shelf.  The 3000i has 15x450Gb 15k SAS (in one RAID6 LUN)  Dell drives.  The 1000 has 15x 1Tb 7200rpm (in 2 RAID 6 LUNs).

I have this hooked up to two clusters of ESXi machines using multipathing and iSCSI on a dedicated iSCSI switch.  This switch also has our original SAN which is similar but more of a mishmash of drives.

The two clusters are 4xr710 and 4xPE2950.

Performance to the original SAN is ok.  It has too many VMs on it and I need to upgrade the firmware.  So we got the 2nd SAN so I could update the first SAN without powering down 60 VMs.

I updated the unit to the latest firmware:

Current configuration
Firmware version: 07.35.39.64
NVSRAM version: N1532-735890-005
EMW version: 03.35.G6.50
AMW version: 03.35.G6.50

I have successfully copied data to the unit and it was performing great until about 2 weeks into production when everything shat the bed.  VMWare storage migration wouldn't even migrate the machines out because it was timing out.  I had to SSH into each host and manually move the machines from the new san to the old san.  This process took a really long time.  I guessed it was transfering at about 5mb/sec.  The average latency on LU0 was over 90seconds (90,000ms), which of course would cause vMotion to time out.

Now I don't know what kind of tests I can perform on this, that's what I'm looking for.  Trying to see if it's a controller issue or if it's a drive issue, back plane...I don't know but I would like to find out.

Thanks!
Josh!

All Replies
  • Hello, Josh.

    I must admit, any sort of 'performance' troubleshooting is going to be quite an endeavor. I generally like to start with my hardware. Let's make sure the hardware is functioning properly, and there are no issues with disks, controllers, etc degrading your performance.

    For this, I'd like you to send me a support bundle. I'll paw through that, and be sure you don't have some smoking guns inside the machine, so to say.

    Next, we'll need to make sure your connections are setup to spec. For this, here's a link to the Support Matrix for the MD3000i: downloads.dell.com/.../powervault-md3000i_Reference%20Guide_en-us.pdf

    At the end of this support matrix are various 'supported configurations'. Use these to verify you're as close to these as possible to how we suggest cabling your environment.

    Outside of that, you'll need to verify the software setup is either, identical to your "functional" stack, or up to spec per our recommendations. For that, here are a few links for suggestions:

    Deploying esx on MD3000i

    www.dell.com/.../md3000i_esx_deploy_guide.pdf

    Wiki page for MD3000i / VMWare config:

    en.community.dell.com/.../3043

    I hope this helps. I'll send an email so you can reply with a support bundle.

    Have a happy holiday!

  • Daniel,

    Did you get my support bundle?  Have you had a chance to take a look through it?

    This SAN is setup the same way our original san is:

    (Figure 5 and 7)

    downloads.dell.com/.../powervault-md3000i_Reference%20Guide_en-us.pdf

    Thanks for all of your help!