RAID Configuration for Server

[opanwar]

Hi guys,

I am working on a project involving ESXi, and my department has bought a dell T610 for it. It has 8 x 450GB HDDs, which I have configured as 2x RAID 5s and one as hotspare. While reading online on various other forums I saw that people have complained about having a degraded performance with RAID 5 and ESX/ESXi. Has anyone else experienced degraded performance? Does RAID 10

solve the problem?

Additional details:

I will be running roughly 40-50 virtual machines on this server.

While answering please consider that I am a newbie in ESXi as well as RAID configuration.

Thank You,

Ojas

[weinstein5]

40-50 VMs is quite a heavy load - what sort of workloads will these VMs be runnings? What type of CPUs are in this box? How much memory? - I ask these because 40-50 VMs on a single host could overload the hosts other resources -

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[opanwar]

These VMs would be used by students for learning configuration of various OS(ubuntu/Win2K3/Win2K8/SUSE etc), so they would typically have 512 MB RAM or at max 1 GB for resource hungry OS like Win 2K8.

Server configuration:

2 x Intel Xeon E5540 @ 2.53 GHz

48 GB 1066 MHz RDIMMs

8 x 450GB 15k HDD

[dtracey]

Hi Opanwar,

For simply running vanilla guest OSes then your configuration will be fine. You only need to start worrying if they are running IO heavy apps such as SQL / Oracle etc! Then it would be worth looking at RAID 10...

Dan

[opanwar]

Thanks Dan, I also am concerned about people leaving their VMs on while not using it and thus wasting system resources. I know that I can do resource allocation to better manage resources, but does it turn off/suspend the virtual machines that are not in use?

Thanks,

Ojas

[azn2kew]

Well, if its just for testing lab then 40-50 VMs wouldn't be any issue since there isn't any application/database loads much at all but rather testing configurations from OS perspective. As far as production goes, standard build would between 10-16 VMs and that varies in terms of loads/services to limit the SCSI Reservation conflict errors and IO thrashing. Seems like these will use local disks for VMFS, if you want you may build a test iSCSI & NFS SAN for free using Openfiler, FreeNAS, Xtravirt VSA, Starwind, StorMagic and for backup these VMs, you can use script from William Lam GhettoVCB to backup them up daily basis in case or any Veeam, vRanger, VISBU, PHD esXpress etc..

If you worries about VM idling and power on, you can schedule task to run a script from the machine to shutdown itself after hours and weekend.

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Regards,

Stefan Nguyen

VMware vExpert 2009

iGeek Systems Inc.

VMware, Citrix, Microsoft Consultant

[dtracey]

Hi Ojas,

As above the virtual machines will not suspend automatically by default, but when you get to this point let me know and we can help with some scheduling and scripting to quiese them!

Thanks,

Dan

[opanwar]

Hi Dan,

Now I have 4 virtual machines on my server(2 Ubuntu and 2 Win2K3). I will start working with scripting and scheduling tomorrow, I would appreciate your help.

I have very little experience with scripting, would you suggest me reading article about any specific scripting language?

Thank You,

Ojas

[dtracey]

Hi Ojas,

The easiest way to do script a shutdown from within a guest is to use the native commands from within that OS.

e.g from within W2K3 you could create a .bat file with something as simple as:

shutdown -f -c "Scheduled Shutdown"

...and then create a scheduled task to run this daily at a certain time. The -f is a 'force' to ensure no application can hang the server, and the -c adds a comment to the System log.

From within ubuntu add something similar to the crontab file:

0 0 * * * shutdown -h now

That runs the shutdown halt command at midnight (0mins 0hours) every day of the year (*).

It's a very simple way of doing things - let me know if you need anything else.

Dan

[srinivasvivek]

If you are planning to use vCenter, you can use "scheduled tasks" for scheduled shutdown of VMs