[TriLUG] Disk subsystem recommendations
claystuckey at gmail.com
Wed Nov 25 16:45:27 EST 2009
The tricky thing is that there are several factors to disk
performance. You have seek time (how much time it takes to find the
data) then you have the read/write MB/s that is quoted. This is
typically sequential read/writes. I expect you will have a mix of
sequential and unordered read/writes in the real world.
While raid-0 does increase your transfer rate, you are still limited
to a single spindle. This means your host OS and VM(s) will be
fighting for head time. I have been running 3 fast sata drives in a
raid0 for a while and have felt that I should have much better
performance. That was until I realized that I can only get 1 piece of
data at a time. I just recreated my volumes as 3 single drives. I have
the host os on 1. The other 2 drives will each get a vm. I expect I
will see a major performance increase for my situation.
If your host/guest machines are performing normal operations (ie: many
small read/write operations), it would seem that seek time and
separate spindles is what you need.
I don't know how solid state drives compare with platter drives. Maybe
they can read/write more than one item at a time.
I will let you know how my performance works out next week.
On Nov 25, 2009, at 4:36 PM, Ron Kelley wrote:
> x2 on the SSDs. $489/ea for the Intel 160GB G2 SSDs
> (zipzoomfly.com). Put a pair in RAID-0 for $1K. Very fast and
> should last a long time.
> On Nov 25, 2009, at 4:31 PM, Joseph Tate wrote:
>> I don't think you want the overhead of LVM. I'd stick with
>> straight partitions.
>> Why not go solid state disks?
>> On Tue, Nov 24, 2009 at 10:02 PM, btncix btncix <btncix at gmail.com>
>>> I don't know much about VMWare nor much about virtualization, but
>>> if your
>>> main concern is performance, I would suggest you keep RAID-0 and
>>> separate partitions. If you're worried about flexibility with hard
>>> partitions, look into LVM for your root partitions and logical
>>> for your boot partitions. Of course, this more difficult to setup
>>> than what
>>> you were thinking about, but it let's you keep RAID-0 and still
>>> create your
>>> VMs with direct physical access to hard drive.
>>> TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug
>>> TriLUG FAQ : http://www.trilug.org/wiki/Frequently_Asked_Questions
>> Joseph Tate
>> Personal e-mail: jtate AT dragonstrider DOT com
>> Web: http://www.dragonstrider.com
>> TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug
>> TriLUG FAQ : http://www.trilug.org/wiki/Frequently_Asked_Questions
> rkelleyrtp at gmail.com
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