Poor disk performance Fedora 10 on Gigabyte GA-G31M-ES2L:

Kernel is Linux-2.6.27.25-170.2.72fc10.i686

This is an entry level board with integrated graphics and four sata-2 ports. I have two Hitachi 500GB Sata-2 drives plugged in and am seeing only 4MB/S when copying files between them. I have tried different combinations of sata-2 ports on the mainboard, but get same consistently bad results.

When I run hdparm -tT, I see 90+MB/S on both drives:

[root@server work-2]# hdparm -tT /dev/sda

/dev/sda:
Timing cached reads: 7782 MB in 2.00 seconds = 3899.22 MB/sec
Timing buffered disk reads: 272 MB in 3.01 seconds = 90.45 MB/sec

When I look at drive mode, I get this:

[root@server ~]# hdparm -c /dev/sda

/dev/sda:
IO_support = 0 (default)
16-bit)
[root@server ~]# hdparm -c3 /dev/sda

When I try to set it to 32 bit mode, I get this:

/dev/sda:
setting 32-bit IO_support flag to 3
HDIO_SET_32BIT failed: Invalid argument
IO_support = 0 (default)
16-bit)
[root@server ~]#

Does anybody know what is going on here?

Thanks

I forgot to mention that the file system on both the source and destination for the copy is EXT4

Some more info:

Disk sda has three partitions:
sda1:ext3 /
sda2:swap
sda3:ext4 /work-1

Disk sdb has one partition:
sdb1:ext4 /work-2

Copying a file in File Manager from sdb1 to sda3 (EXT4 to EXT4) gives about 4MB/S.

Copying a file in File Manager from sdb1 to sda1 (EXT4 to EXT3) gives about 74MB/S.

So maybe the problem has to do with the EXT4 file system? I reformatted sda3 as EXT3. Same slow results!

What's up here?

Just to cover all bases, I re-flashed the mainboard BIOS with the latest.

Yes, you have the latest BIOS...

Have you tried to look at and possibly change the BIOS settings to see if there is something, AHCI or IDE, perhaps, or settings that reserve memory for the graphics chip, that is slowing the system?

Have you tried to download and burn a linux live-cd and used it to copy a large file from each HDD to a USB device or from a HDD to some other location, and see if the process is as slow as using your installed linux for the same operation? Does the live-cd transfer data any quicker between the two HDDs than your installed linux?

I'm having the same problem here.. with both ext3, ext4 or vfat partitions in Fedora 11.


Observing the disk activity, I realize that the read speed downs to almost 0 after the first write, and keeps down for the remaining copy time.

I other words, everything goes ok in the first 5 seconds, when data is being copied from source disk to cache.
After the first cache flush to destination disk, the read speed goes down and keep slow up to the end of copy process.

Can you see the same behaviour? I see that in the gnome system monitor.