lpr/1si disk throughput

[Matt Ostiguy]

Howdy,

I have been trying to tweak out disk performance for backup performance (Veritas backup exec 8.6). I have 2x700mhz/ 512mb ram lpr that I can't seem to get more than 4.5-5MB/s out of on full "copy" backups for testing purposes. I have tried this in both a non raid, and a raid 1 config, with matching 9 gig 10k rpm U2 HP (rebadged fujitsu) drives off of a netraid 1si.

I have also done a full defrag.

I am just kinda suprised that I am not seeing higher read throughput. Anyone have any comparable data for disk performance for lpr's/netraids?

TIA

ostiguy

[kris rombauts]

Hi Matt,

a bit dificult to comment on since you do not specify what backup method you used in the test.

Is it over the LAN ,to a local SCSI tapedrive or to a fiber attached backup device ... ?


The number of files and their size also plays a role (i.e. many small files or few big files)
and the allocation unit size of the NTFS filesystem (i assume this server runs NT/W2K)

The cache setting of the Netraid 1Si is also importent, do you know if it set to write back or write through ? Write back offers the best performance.

Kris

[Matt Ostiguy]

Over lan, to a scsi raid on a backup server. Using the win2k disk perfmon counters, I see that the read bytes/S average stays fairly in tune with the throughput I see in backupexec.

With other agents (exchange, sql) on similar boxes, I do see throughput limited by the network card, and get 10-10.5MB/s.

I just set it to write back, and got a slight jump - I got an even 5 MB/s throughput, whereas before I have seen 4.18 to 4.78 MB/s. The 1si is now set to write back/ normal read policy/ cached I/O, with a 64K stripe size .

I am going to try updating the 1si firmware today

[Greg Carlson]

Matt,

Do you have an external tape device you could cable directly to the LPr to perform a backup and give you a local benchmark removing the network from the equation?

Ciao,
Greg

[Matt Ostiguy]

Don't have a local tape drive - the only ones available would be DLT, whose native throughput is 6MB/s anyhow.

I have tested the network stuff - no problem. I can sustain 10.5 MB/s no problem- I do with database backups of similar HP servers (lc2000r /w raid 5 on a 3si.)

Matt