W. Chris Shank on 29 Jul 2007 19:09:57 -0000


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Re: [PLUG] VMWare performance tuning


The hardware is pretty good (dual quad core xeon, 4G ram). I was considering SCSI instead of SATA (i said USB - no SATA - DUH). I would consider off-loading some of the I/O to a SAN or another server, but how much of an improvement will it really give me?? I wonder if instead of RAID5 across 4 disks I should have 3 mirrors across 6 disks (2 for each mirror) and then put a couple of VMs on each disk mirror.


----- Original Message -----
From: Mag Gam <magawake@gmail.com>
To: Philadelphia Linux User's Group Discussion List <plug@lists.phillylinux.org>
Sent: Sunday, July 29, 2007 1:59:19 PM GMT-0500
Subject: Re: [PLUG] VMWare performance tuning

Chris:

This is a major pitfall of "virtua-LAZY-ation". Have you ever noticed vendors (Vmware, IBM, and Sun)  never mention this during their Roadshows?

Anyway,

here is how we tried to address the problem our environment (AIX APV), the same concepts should appl y:
Backups: Make sure you schedule your backups accordingly. Ie. Only 1 server is being backed up at a time
Use a SAN: Place your vmware images on a SAN and utilize  MultiPath I/O(MPIO) software such as EMC PowerPath. MPIO will loadbalance what adapters are busy and start sending data thru the other Fiber Adapter, this can increase performance by 50% percent. Keep in mind you need atleast 2 adapters.
Striping on Disks: Since you are using RAID5, you are already using this, so don't stripe again :-)
Mirroring: Make sure nothing is mirrored on the guest/client side. Your guest disks should NOT be mirrored, because they are already mirrored and redudant on the host end. This will be costly I/O
Placing data: Try to place your image data across various disks to you can spread the load.
Hardware: Buy new hardware :-). Try to buy more disk adapters (fiber or scsi), to spread the load.


HTH :-)



On 7/29/07, W. Chris Shank <shankwc@acetechgroup.com> wrote:
I have a VMWare server with several VMs on it. The system has a bit of a bottleneck at the disk IO level.  CPU performance is great, but if another VM starts hitting the disks hard, it really bogs down the other ones.  It has 4 USB HDD in a hardware RAID 5. Anyone have any suggestions on what I could do to improve the disk performance?

--
W. Chris Shank
ACE Technology Group, LLC
www.myremoteITdept.com
(610) 640-4223

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--
W. Chris Shank
ACE Technology Group, LLC
www.myremoteITdept.com
(610) 640-4223

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___________________________________________________________________________
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