Topic: Large Disk Performance

[Tim Heinzen]

I've been running into problems with 40 and 80 GB IDE disks.  Copying a large file to my server is 3 X slower on a 7200 RPM / 80GB / 8MB cache disk than the same copy to an old 6GB 5400 RPM disk I had laying around.  It looks like the 40GB disk is just as slow.  Any advice on how to fix this?


Thanks
Tim

[Michael Smith]

Gonna need more info on your hardware to think about this one.

[DG]

Huh? your Western Digital 80GB 8MB is slow??!

Try "hdparm -Tt /dev/hda" no quotes.

I have an old Quantum 2.1GB HDD and get:

[root@phoenix root]# hdparm -Tt /dev/hda

/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.63 seconds =203.17 MB/sec
 Timing buffered disk reads:  64 MB in 34.03 seconds =  1.88 MB/sec

Which is really bad....You should be getting 40 MB/sec for buffered disk reads.

[Jesper Knudsen]

I had the same problem on my new 80G IDE disk but the problem got resolved by upgrading the BIOS and enabling DMA access. My old BIOS did not recognize the new large disk properly and Linux couldn't either. This resultet in PIO access.

I got 3MB/s access before and 22MB/s afterwards.

DMA Access:
http://www.myezserver.com/downloads/mitel/howto/hdparm-howto.html

Rgds,
Jesper

[Tim Heinzen]

You were right.  I followed the instructions on the dma access link :

http://www.myezserver.com/downloads/mitel/howto/hdparm-howto.html

and sure enough transfering a 1GB file to the server went from 12 minutes to under two minutes.  disk access was around 2MB, and it's now 49MB /s if memory serves me right.  I'm to busy trying to get the server into place to do any before or after benchmarking, but this made a HUGE difference.

Thanks to all who replied.

Tim