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HDD choice for virtual setup running 4 x VM's (SBS2011 x 1 & Win 2008 x 3) - SAS or NL-SAS?

Hi all,

Would appreciate some advice with regard to choosing adequate HDD's for my intended virtual setup. I have a couple of systems configured but am having some difficulties choosing between SAS and NL-SAS drives.

My intended setup is:
Running 3 virtual servers (1 x sbs2011 standard | 3 x Win 2008 R2 Standard), using Win 2008 R2 Enterprise as Hyper V host running on a single Dell R510 server. The SBS VM will handle our domain & email roles whilst the other VM's will run the organisation's CRM, FileMaker Pro and other low activity roles. By low activity only approx 5 users connect to the CRM and 20 to the File Maker Pro DB. The SBS VM will service approx 20user but can swell to 60 users.

I have the server more or less complete bar the HDD choice. Normally I always plump for SAS drives but this organisation is not vast and I'm keen not to over spec. Dell has offered up NL-SAS 10K drives as an alternative that whilst not on a par performanace wise with the SAS drives they do offer a significant saving.

Ive not had much experience with NL-SAS drives in 24/7 operation and have read lots of articles and posts both slating performanace and reliability over their SAS cousins but 99% of these appear to be in much larger and more demanding environments than possibly mine will be.

Be keen to know if anyone with a similar setup is using the NL-SAS option and what their experiences have been or opted for SAS and why?

Thanks in advance,

3 Solutions
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
15k SAS
You typically get what you pay for, but since storage pricing spiked big time due to the Thailand flood, then you are paying premiums now.

Why not buy absolute minimum configuration now, to start getting things set up (using the 15K drives), set some baselines and benchmark using your real-world usage.   Then while you decide what you can get away with ... pricing will inch down.

Also, nothing wrong with using both.  Personally, I would create some RAID1s with the 15K drives, reserve for index and table space and anything random or write intensive, then go with slower drives for the actual databases.
Just out of curiosity,how are you going to back up the systems?

You know that USB  pass through from the host machine to the Hyper V VM's is not supported .

So you probably need something like iSCSI to be able to back up the machines for DR.

Let's just say M$ hasn't thought this all the way through.

Vmware on the other hand allows for USB pass through and makes backups and DR  a whole lot more straightforward.

As for the disk issues,SAS is pretty expensive per gig compared to SATA .

Buying disks from Dell is pretty much highway robbery even when there was no shortage.

I personally would do 4 600 gb WD Velociraptors in a RAID 10 as a separate purchase.

Dell only gives you a 1 year warranty on their branded drives any way and if you buy from WD, it's 5 years.
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nellster1Author Commented:
Hi all, many thanks for the replies.

@hanccocka - short and sweet, I like it.

@dlethe - Interesting approach. I could provision VHD's based on SAS RAIDs for more intensive duties and VHD's on NL-SAS for normal file serving with a view to possibly upgrading pending pricing/space.

@pgm554 - System backup will be to a NAS device, then to USB portable drive for offsite. Aware of the "limitations" of the MS Hyper-V but the licenses will not cost us anything for all the OS's so a big incentive to go down the MS route... for now. Had not considered purchasing the HDD's elsewhere actually, for some reason had it in my mind that they had to come from Dell... which of course they dont!
If you obey the software's recommendations on RAM (sbs2011-10GB, win2k8-2gb + apps + overhead =~ 24Gb) then you can go with NL-SAS. (Your users using cached email right? then timing is not critical) But it still would be wise to separate the workload:
VDisk1: Raid1 - VMs operating systems and exchange data - not time critical.
VDisk2: Raid1 - Applications Database data, CRM and others which would need faster responses.

That would be four NL-SAS disks.
nellster1Author Commented:
Hi all, decided to split he points as all extremely helpfull answers.

Many thanks and apologies for delay in answering.


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