raid controller recommendation

[Jesse Keating]

On Friday 12 December 2003 07:10, Henry Hartley wrote:
> At the risk of starting a religious flame war, could you comment on
> the relative performance of hardware RAID in IDE vs. SCSI?  For the
> sake of argument, assume top of the line hardware in both.  Does
> hardware IDE RAID perform as well as hardware SCSI RAID, all else
> being equal (but is it ever?)?
>
> What factor does rotation speed play?  That is, how will an array
> of 16 7,500 RPM drives compare with an array of 8 15,000 RPM
> drives?

Since there are now 10K rpm SATA disks, an array of 16 of those will out 
perform most 8 disk SCSI arrays, although really top end 15K RPM drives 
( not mid quality 15K, super high end) will still perform better.

> I assume the SCSI solution will be more expensive but how much?
> Will the performance make it worth the extra expense?  There is a
> time to be cheap and a time to spend money, Proverbs 3:6 (more or
> less).

For prices, figure ~ 1K for 2 8port 3ware SATA controllers, and $300/16 
for 16 74gig 10Krpm WD Raptor disks.  On the SCSI side, you're looking 
at $800~ for a 2 channel 2200S u320 raid card, and the drives are 
around $600~ for 15K rpm 73gig drives.  If you wanted to use 146gig 
drives to match capacity (8x 146 == 16x 74) then you're looking at 
$700~$800 per disk.  So the prices aren't that much different, but you 
do get more density with the SATA stuff.  I haven't seen any 3u dual 
xeon systems that can sport 16SCSI hotswap disks, yet we sell a 3u dual 
Xeon that supports 16 hotswap SATA disks.

> The specific function for my array will be in a terminal server
> where many workstations are using the same drive array.  The
> cost of the server is expected to be high but won't come close
> to the savings on workstation hardware.  I can afford to be
> (cannot afford NOT to be) a bit extravagant on the server - fast
> CPUs, lots of RAM, big, fast RAID array...

I would highly recommend a RAID 10 setup due to the amount of concurrent 
access happening.  You're probably looking somewhere in the ballpark of 
$15K for a dual xeon 2.4ghz HT system, with 8gigs of ram, and 16x WD 
10Krpm 74gig drives.  Raid 10 configuration will give you 592 gigs of 
space.  If that isn't enough space, then Raid 5 on these drives can get 
you up to 1.1TB of space.

-- 
Jesse Keating RHCE MCSE (geek.j2solutions.net)
Fedora Legacy Team      (www.fedora.us/wiki/FedoraLegacy)
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