Apologies if this is posted in the wrong group, if so could you point
me in the right direction.
I've just built a new home server; operating system is Server 2003 R2
standard. Motherboard is an Intel DQ965GF with a Core2Duo 1.86 and 2GB DDR2 Kingston RAM.
I've been doing some testing before posting so hopefully you'll be able to help me out.
In the system I have 3x500GB Seagate SATA drives and 1x320GB Maxtor
SATA drive. Initially I created a RAID 5 with the 3x500's. I partitioned that into a 30GB for the system and that left somewhere over 900 for the data.
Once it was up and running I updated the drivers and then tested the
drive performance. I used YAPT. Read performance on both partitions
was as I had hoped, it was around 130meg/sec. Write performance on the data partition was 90meg/sec. However write performance on the system partition was only 10meg/sec. I've checked the net and can't find
anything and I've confirmed write cache is on.
The next thing I did was to brake the RAID and have the drives as stand alone. I installed Server on the 320GB maxtor and then tested performance. The 3 Seagates all returned consistent 72meg/sec read and write. The maxtor returned 62meg/sec read and write.
I've now recreated the RAID 5 and installed Server again but all as 1
big partition. Read performance is back up to 130's,eg/sec but write
is still 10meg/sec.
I've tested performance of the RAID when booting off the maxtor and it's 10meg/sec W and i've also installed XP on the maxtor and the performance is trhe same.
On-board RAID 5 write performance is typically poor, which is a typical reason for avoiding them for RAID 5. However, this is worse than I would have expected -- I'd have guessed around 1/2 of a single drive's performance (considering that a write could take a read + write of parity).
I suggest trying different stripe sizes. I presume you've already tried 64k. I'd suggest 64k / (number of data drives) = 64k / (number of drives in RAID 5 - 1).
You could also try a different benchmark program or simple large file copies -- Maxtor to RAID.
heres a small hdd read/write performance testing utility i had downloaded a few years ago, Raptest (its under 100KB), its pretty accurate... after searching google, i found it here (towards the bottom of the page):
Those were with a 1gig file and 2 mins run time. The speeds with bigger tst files is consistent.
The RAID has some 300gig of data on it now so the test file would have been created near the middle of the disc. The Maxtor only has 10gig on it. I'd imagine if both drives were empty the speeds would be slightly faster.
These are really great numbers for on-board RAID 5. Thanks for the post. I'm going to think about getting one for myself and then dropping this "you must get an add-on controller for good RAID 5 writes" business.
The read performance test is not entirely reliable if you have a ton of RAM. At even around 60 MB/s, reading for 2 minutes = 7.2 GB read, which exceeds your test size significantly. So if the some or all of the data fit in cache, you'd get incorrect results.
But it's harder to fake/cache out a write performance test (assuming that the data is changing / cache is not that smart to detect unchanged data for writes), and as the numbers roughly match a 2-drive RAID 0 expected performance, I'm starting to believe them.
Did you happen to enable write back cache on your 05 raid array? After reading Toms review on the ICH8R, I was really skeptical, because the highest I have seen before that is around 10-20 MB/s
Here is Tom's Review: