Many hard drives - server storage

[meester]

I have no familarity with anything other than desktop hardware.

So I'd appreciate some explanations on how things work in the server world.

Let's say I bought this case:

http://www.newegg.com/Product/...x?Item=N82E16811219021

and filled with 20 hard drives.

How would you typically configure those drives? What protocols would be used?

Are there any implications for the bus of having that many drives installed (i.e. is there sufficient bandwidth)?

And for my application, which is VMs, how would cheap single drives compare to a RAID array of faster ones? How many Windows XP VMs could you run simultaneously on a single 7200rpm SAS drive before the hard drive becomes a major performance constraint, and how would that compare with a RAID array of 10,000 or 15,000 rpm drives?

 

[Elixer]

For one thing, VMs want (need) lots of RAM. If you are running more than one, then you need to be on a 64bit OS, so you are not limited to under 4GB.

It also depends just what virtual machine monitor you are running, what VMs, and how many. Just what are your plans to do with all these VMs?
Would you then dedicate one HD for each VM, or do you want some redundancy protection for the VMs as well? Again, it just depends on what your overall plans are.

 

[tynopik]

you get something like this:
http://www.newegg.com/Product/..._-11-119-122-_-Product

which easily handles 12 vm drives + system drive + optical drive + a spare (using 2 4-in-3 adapters)

> How would you typically configure those drives? What protocols would be used?

you would get a 1366 board with 9-10 sata connectors and then add a card like this to get another 4 sata connectors:
http://www.newegg.com/Product/...x?Item=N82E16816115029

(or http://www.newegg.com/Product/...x?Item=N82E16816115026 for 8 more connectors)

note: this is only to be used as plain drives, i wouldn't recommend this card for raid setups

> How many Windows XP VMs could you run simultaneously on a single 7200rpm SAS drive before the hard drive becomes a major performance constraint, and how would that compare with a RAID array of 10,000 or 15,000 rpm drives?

well it totally depends on your workload. how much disk access do they need? and how often are the demands going to be simultaneous?

if they're mostly hitting the disk for swapfile reasons then adding ram is obviously the superior choice

a raid will be faster servicing any one request, but if you start trying to process multiple requests it may be slower than individual drives unless you have a really top-notch controller

you can always start small and keep adding drives as required to see how it impacts performance

 

[Emulex]

dl380 g6 (or dl385) performance server (redundant everything) X5570 * 2
16 2.5" 10K sas drives [optional sas cage] raid-10/split 2 arrays 8 each
extra p410/512bbwc controller to second cage
12 4gb dual rank RDIMM-1333 ECC

nifty thing vmware has clustered storage and memory optimization; it sounds like you want to do some sort of VDI(view) to manage a bunch of machines centrally?

figure 1-2gb overhead for vmware, then you could oversubscribe your XP ram a good bit maybe squeeze out 40-50 machines if they don't work too hard.

Need to consider a disaster recovery plan since you'd be betting alot on one server.

if you are doing this for consolidation vmware has some really nice product that can help mangement of all the vm's a breeze. maybe you should tell us your objective?

(i'm all for whiteboxing pc's but vm farms really belong to quality brand servers). just my opinion.

 

[jimhsu]

If you want cheap: http://blog.backblaze.com/2009...d-cheap-cloud-storage/

That thing is strictly for storage. It probably has unimaginably poor IOPS for that number of hard drives, but it serves its purpose well - a huge freaking file server.

 

[CurseTheSky]

Originally posted by: jimhsu
If you want cheap: http://blog.backblaze.com/2009...d-cheap-cloud-storage/

That thing is strictly for storage. It probably has unimaginably poor IOPS for that number of hard drives, but it serves its purpose well - a huge freaking file server.

I found that really interesting. The only thing I found disappointing is that for all 45 hard drives in each enclosure, they use:

Seagate ST31500341AS 1.5TB Barracuda 7200.11 SATA 3Gb/s 3.5?

I wonder what their failure statistics are. AFAIK, those are the exact drives that have given plenty of others nightmares.

 

[pjkenned]

I'm using 15+ of the 7200.11's, 10 of which are in 5 in 3 backplanes and are running 24x7 and have had no problems with the new firmware. TBH at the price those things sell for (I bought tons from Dell at <$100 in like Feb) I wouldn't be surprised if that was one of, if not the highest volume 1.5+ TB drive out there. Higher volume = more complaints, especially on the older firmware which was no good.