Vmware Hypervisor SATA Storage

[wayneb14]

Hi, I'm building a new server that I plan to install VMWare Hypervisor (ESXi 4.x) on but it will be using 3 x 500GB SATA hard drives formatted to RAID 5, and hot swappable. Will this work ok for storing my VM's on? I'm getting mixed feedback.

Many Thanks

[mcowger]

You are probably getting conflicting feedback because it depends.

1) Make 100% certain you have a fully supported adapter.  Most of the builtin/cheap ones are not HW raid and wont work in RAID more with ESX.

2) Whether SATA is acceptable depends on your workload - whats your planned workload(s) for this host.

[wayneb14]

Hi, I'm being told that it's HW raid, and specifically being fitted with Hot Swap Bays.

Spec is Intel Xeon 2.50Ghz, 8 GB RAM, 3x500GB SATA drives formatted to raid 5. I'm planning to put 2 VM's on it, My Exchange 2003 Server and either my DC or an Application Server .

Thought i'd try out the free hypervisor before going full blown vsphere.

[a_p_]

Which HW RAID controller are you using? That's important! Does it support battery buffered write cache for write-back operation? If not, you will not have a good disk performance. In addition to this you should consider to use at least 4 disks on your RAID5, since RAID5 with 3 disks is one of the slowest RAID configurations.

André

[J1mbo]

Agreeing with what has been written already, just buy another disk and run it raid-10 (with the same capacity).  Provided the controller has battery-backed write-cache and the array is configured for write-back mode, performance will probably be fine (of course, depending on how many exchange users and how heavily they are pounding it!).

Also it is advisable to use 'enterprise' sata drives, for example Western Digital's RE-x range, because the firmware of desktop drives can conflict with the raid controller, resulting in drives being dropped from the array for no reason.  If the controller supports sata NCQ then performance should really be just 7/10's of a SAS-10k array of the same configuration.

HTH

[mcowger]

I'd check to make sure its a properly supported RAID card....

[samansalehi]

I beleive the performance in sata hard drive is very slower, and you feel it if you use SAS hard drives.

Second i HW raid drive for my 4 sata hard drive, and it looks it is not supported in ESXi.

So i try another raid solution , but it takes a lot of time.

at the end, if you can change the hard drive to enterprise, else i think raid 1 for your 2 of hard drives is better.

Saman

Wait for your response

[wayneb14]

Hi All, Thanks for your replies, i'm kinda getting the impression to go with maybe a RAID 10 if I stick with SATA drives? Or should i go with SAS drives, although i think my costs will then go up?. I'm not a big organisation , only around 70 staff so just really want to make sure i get it working right.

[J1mbo]

Really the IOPS rates of the existing servers need to be monitored for a time to determine the required disk spec.

[wayneb14]

Hi, After lots of going back and forth with suppliers with the suggestions you've given, eveything seems ok re: hardware (see below), i'm now being told to add the battery backed write cache is going to considerably increase my cost.

Xeon Quad Core X3440 2.53Ghz 8MB Cache
4 x 500GB HDD
4 x 1333Mhz DDR3 2GB
6 x Hot swap bays
NIC card on MB Vmware compatible
RAID 5 on 3 HDD (Hardware RAID compatible with ESXi 4) Hot spare on 1 HDD
SAS to SATA convertable controller

so my question is:

a) If i stick with the 4 SATA drives and RAID 5, and don't have the battery backed write cache. is it really going to cause disk performance issues, since i'm only going to stick 2 server VM's (Exchange 2003 and a DC) on it? and only have 65 staff and 5 servers in total. The DC is an old P4 2.0Ghz 2GB RAM on a Proliant ML310 G1, so slow as it is.

b) If i went with SAS drives do i still need battery backed write cache ability?

I don't need a all singing and danncing setup but want to get myself potentially ready for virtualising all at later stage.

Thanks for your time

[J1mbo]

Forgive me for being blunt, but I don't see much to suggest that your supplier has much experience with ESXi as the battery-backed cache really is a necessity, and a three-drive raid-5 configuration is really sub optimal.

It could be worthwhile to look at a branded server.  Cost effective RAID cards with battery-backed write cache do exist, for example Dell's Perc 6i is under £300.

Anyway, hope this helps.

[wayneb14]

Hi, I'm finally got a supplier to quote me on the following:

Dell Poweredge T310, Intel Xeon Quad Core X3440 2.53GHz

8192MB Memory, DVD+/-RW Optical Drive

C6 Cabled for RAID 5,

3yr Engineer On-Site, Next Business Day Warranty

4 x Western Digital 500 GB SATA Drives (Installed)

3ware Raid Controller Card with Battery Backup Cache

This should be ok yes?

[J1mbo]

I can't comment on the 3ware card as I haven't used one.  I don't see it as an option on Dell's configurator?

But anyway, looking at Dell direct, US $ 2,400 will buy a hot-plug T310 with X3440, 8GB as 2x 4GB, perc-6i, 4x 500gb hot-plug drives, redundant PSUs, iDRAC, dual-port nic, 3yr on-site.

Whatever you go for, make sure the RAM is specified to  leave as many empty slots  as possible, as 8GB will likely be the  restricting factor with this box.  Especially if you're purchasing  vSphere (and with support), it is also important that the server is  vmware certified too.

If more Windows servers are  planned in the near future, besides needing more RAM, it may also be  worthwhile to get an OEM 2k8r2 Enterprise license with the box.

[Dave_Mishchenko]

I don't beleive you'll get health data for the 3Ware controller in ESXi, but you will with something like a Dell Perc 6i.  As noted, make sure you're able to add memory.  You'll likely run low on that resource first.

[EricBates]

No. The 3Ware does not show health status; however, there is a command line tool (tw_cli) which can be installed directly onto ESXi (download ESXi version from 3Ware -- sorry I don't have the link). Our plan is to write a Nagios script to execute the tool via ssh and parse the results. It's a DIY hack. The Dell PERC would be easier to deal with.

3Ware tech support is generally very helpful. They have ESXi drivers for their cards which can be installed on ESXi embedded. The cards are real RAID with battery backup. Buy the batteries separately.