1 SATA drive very slow, other 2 are fine

jsteel · 06-04-2010, 03:56 PM

Hi,

I have 3 SATA drives in my desktop computer. I recently started copying large amounts of data around and noticed that the read/write performance of one of my drives was very poor.

"hdparm -t" shows 2 of my drives to be 70 and 100MB/s and my slow drive reports back to be just 6MB/s (which is what I am getting while copying data to/from it).

I've taken a look in the BIOS and cannot see any difference between the drive settings. Any ideas?

Thanks

harry edwards · 06-04-2010, 05:35 PM

This link covers some good troubleshooting topics related to SATA drive. It is mainly directed at Lenovo Thinkpads, but, the commands they use may help you determine what's going on.

jsteel · 06-05-2010, 02:45 AM

Thanks. I found the "hdparm -m" setting is set to off on my slow drive. My other drives are set to "on", but when I try and turn it on on my slow drive, it gives a warning message saying that changing this could be dangerous. Not sure I want to risk it!

jsteel · 06-05-2010, 03:39 AM

I read that in rare cases it could cause damage to the file system, rather than the drive so I gave it ago:

# hdparm -m 16 --yes-i-know-what-i-am-doing /dev/sdc

/dev/sdc:
setting multcount to 16
HDIO_DRIVE_CMD(set_multi_count) failed: Input/output error
multcount = 0 (off)

... but it doesn't like it :\ I've tried other settings such as 8 and 32 and I always get the same error.

jsteel · 06-05-2010, 04:30 PM

I just noticed in the Disk Utility that my slow drive is being detected as a SCSI drive. It's connected to a SATA port like the other drives. How can I force this to be detected as a SATA drive? (remove SCSI support for example?)

harry edwards · 06-05-2010, 05:29 PM

It could be Linux is missing the drivers to fully support that drive. Does this help.

jsteel · 06-06-2010, 04:49 AM

Quote:

Originally Posted by harry edwards

It could be Linux is missing the drivers to fully support that drive. Does this help.

I'm afraid I didn't find any help there. It's a fairly new Western Digital drive. I have another similar WD drive that works fine, and the 3rd is a Seagate (also fine).

ktm_kannan · 06-06-2010, 07:33 AM

does your motherboard has different colored SATA ports?

jsteel · 06-06-2010, 09:17 AM

Nope, all the same; 4 red. Changing ports doesn't make any difference.

I'm running Ubuntu 64 bit. I tried Ubuntu 32 bit and got an increase from 6MB/s to 13MB/s. I then tried Fedora (both 32 and 64 bit) and I get 22MB/s (with both versions). This seems far more reasonable, but still pretty slow for a hard drive.

As far as I can tell, all hdparm settings are identical in Ubuntu and Fedora. Fedora also sees this drive as SCSI.

amani · 06-06-2010, 10:44 AM

it may be due to aggressive power saving

jsteel · 06-15-2010, 02:35 AM

All settings related to power saving that I can find with hdparm are the same as the other drives.

I've tried Debian, and that gives about 13MB/s like Ubuntu does.

Any more ideas?

H_TeXMeX_H · 06-15-2010, 04:26 AM

Are they all on the same SATA controller ? or on different ones ? They're usually color-coded on the mobo.

jsteel · 06-16-2010, 04:33 PM

They are plugged into 3 of 4 red SATA connections clustered together; 2x2. Changing them around makes no difference.

I would be partially happy if I could get a consistent speed between distributions, even if that's 20-ish MB/s.

H_TeXMeX_H · 06-17-2010, 04:32 AM

oops, looks like my question was asked before.

Well, if they are all plugged into the same controller, that means the drive itself must be the problem. Can you run smartctl on it. Like 'smartctl -A' and maybe do a short or long test.

jsteel · 06-17-2010, 09:22 AM

Tried running tests on it with smartctl and read the SMART data; all looks fine. Can post results later if needed.

I replaced this drive with a 2.5" SATA drive (only other drive I had handy) and I get very similar results; should a 2.5" drive give between 10MB/s and 20MB/s on various Linux distributions? I thought these would give about 50MB/s?