This is but a single data point, but if others can provide some
additional data, it might help you triangulate what you want.
I'd also recommend 3ware over Areca - I've had 2 bad experiences with
Areca involving data loss - only one of which I could really blame on
the controller, but 3ware service is very good (as such things go).
Here's the bonnie++ output on a backup server I built for a lab:
This was on a very baseline box (single athlon64/.5GB RAM) outfitted
with a single PCI-X 3ware 9550SX-12 controller driving 12 SATA-2,
NQS-enabled 500GB WD disks in RAID5 with an XFS file system, 64K
stripe, with readahead set to 16K (blockdev --setra 16385 /dev/sdb)
Email me if you want the exact spec.
Here's the bonnie++ output (it looks like it's going to be fragged by
the line wrap tho - I can send you a file that will protect it and
provide more details in it as well). It'll be cheaper of course now.
The disks were on the 3ware approved list and were also among the
cheapest available. The SATA2 spec and the NQS makes a huge
difference. If you have to down-grade the disks to SATA1 (via
jumper, because of controller incompatibility), performance drops to
~1/3.
The salient number is 206298 KB/s for block writes and 543326 KB/s for
block reads. When I was doing some benchmarking on climate data
reduction (netCDF files), I got real-world numbers close to what
bonnie++ indicated. Of course character performance is relatively
awful. And this is an XFS filesystem - as others noted, you'd
probably want reiserfs (or maybe jfs?). If you keep the journal on
another controller, you should also get better performance.
Also note, this is with RAID5. If I had really tried for maximum I/O
with RAID 0 or 10, it should have been even higher.
Version 1.03 ------Sequential Output------ --Sequential
Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per
Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP
K/sec %CP /sec %CP
kstore 15000M 57150 96 206298 42 113941 29 63148 99 543326
55 231.6 0
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 6081 31 +++++ +++ 5702 24 7243 35 +++++ +++
1448 7
kstore,15000M,57150,96,206298,42,113941,29,63148,99,543326,55,231.6,0,16,6081,31,
+++++,+++,5702,24,7243,35,+++++,+++,1448,7
--
Harry Mangalam - Research Computing, NACS, E2148, Engineering Gateway,
UC Irvine 92697 949 824 0084(o), 949 285 4487(c)
[EMAIL PROTECTED]
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