Dismal performance - Software Raid

[kokhong]

I had been testing DSS lite on 2 different hardware and seems to be getting dismal performance of around 2% of GbE when transfer a single 1Gb file from a T60 with GbE connection on XP-SP2 to the iSCSI volume. When transferring to the NAS share, the network bounce between 2%~14%.

Platform 1
Celeron 2 Ghz with 1Gb RAM on i945 mini-itx with 2x Marvell GbE. NAS and iSCSI Volume in RAID5 - 4disk array (4x 250Gb, Seagate/Maxtor)

Platform 2
Celeron 420 with 1Gb RAM on Supermicro PDSMi-LN4+. NAS and iSCSI Volume in RAID0 - 2 drive array (2 x 250Gb, Seagate).

I'll likely swap the Celeron 420 with a X3210 Quad-core just for comparison. Likely to get the 3ware 9550 later.

At 2% of GbE, the transfer rate is only around 2~3 Mb/sec. That's shockingly slow. Is that the normal performance of Open-E? Or am I missing something here???

I would expect any standard linux distro to be able to handle 20~30 Mb/sec ie 20~30% of GbE bandwidth and a dedicated distro like Open-E to be able to reach 40~50 Mb/sec for RAID0 volumes.

[To-L]

hi kokhong

you should be getting better performance than that
do you have write back enabled, also check cache size
are you using hardware or software RAID?

[kokhong]

Hi Torpedo,

I've changed some BIOS settings, selected Enhance SATA and Intel RAID and found that the system was much faster, able to reach between 20%~30% of GbE for iSCSI. That's a more respectable 30Mb/sec for a 2 drive software RAID0. Not fantastic, but useable.

I'll try out a 4 drive RAID5 configuration before sourcing for the 3ware 9550. Hope that would be able to push the performance closer to 60Mb/sec. That would make disk-to-disk backup more reliable.

Thanks,
Kok-Hong

hi kokhong

you should be getting better performance than that
do you have write back enabled, also check cache size
are you using hardware or software RAID?

[beng]

Ummm... hate to be pedantic but 30% of a GbE is 300Mbits/sec which is actually a pretty good speed :-) especially for iSCSI.
Cheers Ben.

[kokhong]

Hi Beng,

That may be so...but gathering benchmarks figures for the 9550SX, it seems possible to get 200~300 Mb/sec for RAID5 volume. In light of that, a 40Mb/sec iSCSI performance seems to suggest that there's a lot of headroom for performance tweak.

I've used IOMeter, Intel NASPT to get the 40+ Mb/sec readings for RAID5 iSCSI/NAS reading. It would be great if others can share their experience with configuring the 9550SX for best performance with Open-E.

Ummm... hate to be pedantic but 30% of a GbE is 300Mbits/sec which is actually a pretty good speed :-) especially for iSCSI.
Cheers Ben.

[beng]

G'day Kok-Hong,
I'm just a little confused here, in one paragraph you state:

able to reach between 20%~30% of GbE for iSCSI. That's a more respectable 30Mb/sec for a 2 drive software RAID0.

So the implication is that you are getting 20-30% of 1000 Mbit/s or 200-300Mbit/sec, but the next line you stated 30Mb/s so I assumed you meant 30MB/s(30MBytes or 240Mbits/s), which in my limited experience is pretty good for a 2 Drive Raid 0....

I don't use the 9550, or Onboard Raid for that matter, but I can say that I get around 160-180 Mbit/s Read with an Adaptec 5805 in Raid 5 with 3x Seagate 500GB.

Cheers Ben.