Summary: Performance & cost of SAS 2.5" disks, Solid State Disks & SAN disks

Thanks for the replies, appended below the responses :


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Alternatively, buy an HP Proliant, fill it full of 1Tb SATA drives, use a
P400i
 Smart array controller with the 512Mb BBWC and save yourself a ton of
money.
 Runs Solaris x86 just fine.

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b) is my choice - Fast good IO - Expensive
a) Cheap - Slow IO
Internal disk and external fibre HBA IO almost the same.

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There's actually less latency if the RAID controller is inside the server
rather
 than seperated by a but of glass so there is a slight improvement; of
course
 the application may queue enough I/Os so that latency doesn't matter.

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won't that depend on the hba you choose?
4gb and 8gb are the choices for the hba.
i, personally, would prefer to have a netapp array
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your RAID setup counts (be it in the server or SAN) :
RAID 10 same read speed of RAID 0, half th write speed assuming equal no of
disks.
RAID 5, (N-1)/N of the read speed of RAID 0, 1/4 of the write speed assuming
same no of disks.
RAID 6, (N-2)/N of the read speed of RAID0, 1/6th of the write speed
assuming same no of disks

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Rotational speed means little. You have to test actual HW.
if you are running Oracle DB, main factor for oracle is SGA size, since
Ora11
auto-tunes that - system memory amount is important.

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To improve on IO throughput, separate volumes that have the highest traffic
onto
 separate spindles, separate controllers.
Are your RAID groups optimal? The more spindles spinning the problem, the
better.
 This will take a bit of effort, because you're attempting to avoid
contention
 for the spindles by having concurrent I/Os on separate RAID groups, but
 maximizing the spindles working on any particular problem. I.e. if you have
1
 LUN that is a performance hog, throw spindles at the problem; if you have 2
 performance hogs, split 'em between RAID groups and controllers to
facilitate
 concurrency.
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I use the following URL for disk specs, pretty similar for other
manufacturers
 since they all use the same disks, taking the first in the list (HP 300GB
6G
 SAS 10K SFF) 4ms average seek, 3ms for half a turn =7ms per I/O = 142 IOPS,
 and a couple below (HP 146GB 6G SAS 15K SFF) 2ms for half a turn 2.58ms
 average seek = 4.58ms per I/O = 218 IOPS.
http://h18000.www1.hp.com/products/quickspecs/12244_na/12244_na.HTML
Don't forget that also if you use the smaller capacity disks you may need
more
 of them and more spindles = more speed as well.

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Was told by a vendor that the SAS disks performance for Sun T5240/T5440 is
 comparable to that of most SAN's disks and if we get Solid State Disk (SSD)
 for the Sun T5240/T5440, that's going to be even much faster as SSD does
not
 have seek time (it's sort of NVRAM storage but of course it's a lot more
 expensive and the largest SSD for Sun is only 36GB? )

On Sun, Nov 1, 2009 at 1:50 AM, sunhux G <sunhux@gmail.com> wrote:

> Hi
>
> I'm comparing which option will give me a lower cost in terms of $
> per nett useable disk capacity & disk throughputs :
> a)local SAS disks (used in Sun T5240) server
>    (looking at 300GB ones of 10000rpm) with RAID 1+0.
>
> or
> b) Netapp SAN disks which the T5240 connects to via
>     fibre HBA connections (with redundancy  RAID 1 built in)
>
> Also, between the two which one would give better IO throughput?
> Is the local internal IO bus of the T5240 to its local disks better or
> to external SAN via fibre HBA?
>
> What about SSD (Solid State Disks that Sun is offerring for its coolthread
> series? - think this one has sort of memory / NVRAM disk with zero seek
> time?
>
> Thanks
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