Topic: Slow Raid?

[Gman]

I setup a mirroring raid on a PIII 400mhz with two 40GB driver and I only get 3.71MB/second. One drive is the primary master and the other drive is the secondary slave. Is there anything I can do to increase performance?

[mike mattos]

I bought an old IBM SCSI RAID controller for $30, it handles up to 2 GB drives quite well!  A newer card will not have this limit.  But for $30, I got a heck of a boost from the IDE system.

Using IDE drives, I believe that you will cut performance by half compared to non raid on the same drives, since the hardware isn't "parallel" compared to the SCSI raid which puts each drive on a separate channel.

One other option might be a massive increase in memory.  

mike

[Max]

Not sure if this has anything to do with your speed issues, but you say that one drive is primary master and the other is secondary slave. Do you have a secondary master? Because you should not have a slave without a master.

[NickR]

Remember that SME does not turn on DMA by default - try running this:

/sbin/e-smith/config setprop hdparm status enabled

After a re-boot, you should see a significant improvement in speed...

[Gman]

The secondary master is the cdrom. I didn't know how to change it to be a slave drive since the jumper configuration wasn't on the drive...

[Gman]

Very good idea!! I tried using htpdarm to turn on dma but it wouldn't work because it is a raid device. I know get the following speed:

/dev/md1:
 Timing buffered disk reads:  64 MB in  1.64 seconds = 39.02 MB/sec