VMware Cloud Community
DARKGuy2008
Contributor
Contributor

IBM x3650 M3 Slow HDD performance?

Hey guys Smiley Happy

I've been getting puzzled at the slow HDD performance I'm getting when installing Windows Server 2008 in a VM. This is the scenario:

I'm creating a VM with these settings:

  • 20 GB HDD (SCSI mode)
  • 2 GB RAM
  • 1 CPU, 4 Cores
  • VMWare LSI SAS adapter

I'm working with two servers. Same brand & model, different places. It's an IBM System x3650 M3. ESXi 5.0.

Installing the OS takes about 1 hour. You'd say this is OK (maybe?) but then I download VMWare Player and install the same OS with the same hardware in my i7 w/4 GB RAM and Win7 and it takes around 10 minutes. So my desktop computer is faster than the super server?

I certainly feel something is wrong here. Both servers are practically empty, no other VM are hogging their resources.

I'm not the sysadmin so I didn't do the server install. I suspect it must be something with the RAID array. I told the sysadm guy and he did some work on rebuilding the array but I don't have much details, neither does he, that's why I'm writing here, to see if any of you guys could shed some light in this puzzle.

Any help is greatly appreciated!

- DARKGuy

Tags (5)
0 Kudos
4 Replies
vmroyale
Immortal
Immortal

How are you installing the OS - via ISO or physical media in the host?

Are all (or any ohter) operations slow, or is it just the install of the OS?

What disks are in the RAID array - is it all local storage?

Have you verified that all components are at the required firmware levels, as specified in the HCL?

Brian Atkinson | vExpert | VMTN Moderator | Author of "VCP5-DCV VMware Certified Professional-Data Center Virtualization on vSphere 5.5 Study Guide: VCP-550" | @vmroyale | http://vmroyale.com
0 Kudos
vlho
Hot Shot
Hot Shot

Hi DARKguy,

do you have raid controller with cache and battery pack?

VM running on ESXi (datastore with vmfs) are very slow if write back cache mode is not enabled on controller.

This feature is possible only on controller with cache and battery.

DARKGuy2008
Contributor
Contributor

Hi! thanks for the prompt reply guys!

I got green light on messing with the server to see what's up with it and what did the IT guys do to it. Here's the deal:

Its got an LSI ServeRAID M1015 SAS/SATA Controller, with 3 500GB (SCSI? it looks similar to SATA but without the separation between power & data) HDDs in RAID 5 (so it makes up a 1 TB drive, or so it says). It does not have battery cache (according to LSI config app) so I assume there's no write cache. I also saw some weird settings on the BIOS so I decided to fix them up (IDE/SATA working as Compatible instead of Native, no Vt-d) and do another test.

Here are the answers to your questions:

How are you installing the OS - via ISO or physical media in the host?

ISO on Datastore 1

Are all (or any ohter) operations slow, or is it just the install of the OS?

First time we got reports on everything slow as hell. The server was remade and nobody has whined about it yet, but OS install is (was?) painfully slow. Well, compared to my desktop PC...

What disks are in the RAID array - is it all local storage?

500GB x 3 in RAID 5.

Have you verified that all components are at the required firmware levels, as specified in the HCL?

The HCL only mentions to call IBM, according to this: http://www.vmware.com/resources/compatibility/detail.php?deviceCategory=server&productid=14358&devic...

Also, I went to the virtual drive's settings in LSI app and "Cache" was on NoChange, I set it to Enabled just to make sure I enabled some kind of cache in an attempt to help.

Well, any suggestions & ideas are welcome! I took a bunch of pictures of the BIOS & LSI settings in case you guys need more info Smiley Happy

Thanks in advance!

0 Kudos
a_p_
Leadership
Leadership

From what you write I expect that you don't get more than ~5-10MB/s!?

As mentioned by vlho it's important to have battery-backed cache for the controller to allow it to safely operate in write-back mode (opposed to write-trough mode). Another performance issue is the RAID configuration. A RAID5 with 3 disks is probable the slowest configuration you can have. Due to how RAID5 works, no simultaneous write operations are possible because this RAID level needs to lock 2 disks for each write operation (data and parity disk).

What I would recommend is that you get a write-back cache option (I think IBM calls it BBU) for the controller (512MB or more) and add at least a 4th disk to the RAID set.

André

PS: Do not try to enable caching without BBU, this can result in data loss in case of a power failure!