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ESXi setup question

We have a question about the following ESXi setup, this is the configuration:

- 1 Intel core i5 650 CPU
- 16 GB DDR3 dual channel 1333Mhz
- 4 320GB 7200 RPM disks
- 1 GBit NIC
- 1 Asus P5QL-VM DO motherboard

Esxi 5.0 is installed on one of the 320GB disks. After the installation we converted a sbs 2008 server to the esxi server. Than we created a second empty virtual disk to create a software RAID in Windows. We did this for the C and D drive. so you have 2x drive C as VM disk in RAID1 and 2x drive D as VM disk in RAID1, each vmdisk is on a seperate harddisk.


All seemed to work well for about a week, but very often on irregular bases, the server becomes slow, users can't access databaes or files for a while, outlook freezes, licensing servers fail,...

We have reasons to believe that the RAID setup we've created is not the best solution. We were wondering if RAID5 in Windows would be a better option?
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Most Valuable Expert 2015
You should setup the RAID array at the hardware level. If the built-in RAID controller of that mainbaord isn't supported by ESXi it is probably better not to use RAID at all, or get an add-on card that is supported by ESXi. Check the ESXi HCL for supported products.
We run our ESXi servers from SD cards here.  That's the way Dell pre-configured them, but it's turned out to be a really good way of doing things.  Here's an article which agrees:

If you run ESXi from SD or USB stick you can then configure your 4 disks as a single RAID 10, which would give you excellent performance and redundancy - or RAID 5 if you need the extra space.

As rindi says, it's best to get your RAID done through hardware. Not only will that give you much better performance, it will then be much easier to allocate available disk to whichever VMs you like as it will appear as a single datastore.
Distinguished Expert 2019
Can't think of an enterprise 320GB 7.2K disk so they're probably desktop drives. Throw them away, get a decent RAID controller with battery backed write cache, use 10 or 15K disks or at least server grade 7.2K ones and use RAID 10 with as many disks as you can get in (or SSDs if you can afford them). Avoid RAID 5 since it's too slow for writes.
Most Valuable Expert 2015
From what I can see in the manual of that mainboard it isn't a server board anyway, with no RAID controller. From the way it sounds you are actually using that as a production server!

You should really get a real server that is on the ESXi HCL and then build your system on that, especially if you are using it in a production environment.
I've worked in small companies before with little or no budget for proper server computing resources.  It's almost always a false economy, but it can be difficult or impossible to persuade management that a "proper" server is required.  

If you are stuck with that hardware the best you can do is try to persuade management to let you get a decent SATA RAID controller (assuming your current disks are just standard SATA?); but better performance and reliability would come from some replacement server-grade SAS 10K or faster disks and a good SAS RAID controller.

We've been really pleased with our Dell R710 servers.  Plenty of redundancy, from the SAS RAID through to the twin power supplies, easy to configure and good performance throughout. Yes, it costs a lot more than a desktop Core i5, but I really can't afford the downtime or hassle of maintaining a cheap cobbled-together system.
Distinguished Expert 2019
If they are desktop disks they'll keep dropping off a decent RAID controller since they won't have TLER/CCTL/ERC so won't respond fast enough if they retry a dodgy block a few times.


I guess the answer is clear, thanks for the replies everyone.


The answer is clear enough.