I'm trying to find out why my disk performance is so slow -- 150x worse
than a comperable system -- and what I can do to improve it.
I've got a system with a painfully slow disk. The worse as it's serving
as a Samba server for a small domain (ten workstations). Saturated
802.1g WiFi is disk-starved presently. System response under any I/O
load is glacial. 'top' routinely reports load averages of from 2 to 10+
with 99% idle CPU. Memory utilization is generally nominal, and was
*not* an issue in the tests below, though disk performance pretty much
precisely sucked.
Using hdparm, I'm getting disk reads at 128 kB/sec. A comperable drive
on a similar system rates nearly 150 times faster[1], at 18 MiB/sec.
I'd expect the slow drive to be capable of similar. 2.4.25 kernel on
x86 HW. All reports following are with the system booted single-user
and running minimal services.
I *am* applying hdparm options including both DMA and UDMA (either mode
2 or 4, not entirely sure).
Specifically:
# hdparm /dev/hda
/dev/hda:
multcount = 16 (on)
IO_support = 3 (32-bit w/sync)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 4982/255/63, sectors = 80041248, start = 0
The disk is a Maxtor 54098U8 40 GiB UMDA66 drive.
It's S.M.A.R.T capable, and I've run some additional diagnostics using:
- hdparm (-i -tT and no options)
- smartctl (-L -S -X -a -c -g -i -L and -v options)
- badblocks (no results when I left)
- bonnie++ (a disk testing utility -- no results when I left)
- Additional diagnostics: cpuinfo, dmesg, free, iostat, lsmod, lspci,
and the /proc/ide/piix file.
The results may be seen at:
http://linuxmafia.com/~karsten/slow-drive/
Comparative results for a fast system similarly configured (but
different HW) is at
http://linuxmafia.com/~karsten/slow-drive/fast-drive.tar.gz
I installed the ide-smart and smartsuite packages, with which I'm pretty
unfamiliar. One result which appears interesting, though I'm not sure
it's significant, is the output of 'smartctl -v /dev/hda', which shows a
large value in the Raw Read Error Rate attribute's Raw Value (smartctl
-a /dev/hda):
Vendor Specific SMART Attributes with Thresholds:
Revision Number: 16
Attribute Flag Value Worst Threshold Raw Value
( 1)Raw Read Error Rate 0x000a 253 252 000 343037
( 3)Spin Up Time 0x0027 182 179 063 27627
( 4)Start Stop Count 0x0032 253 253 000 1910
The other drive has 0 rather than 343037.
I see *no* CRC or other errors in /var/log/syslog or /var/log/kern.log.
syslog is largely uninterrupted series of "MARK" entries.
I do find a number of similar postings googling for 'hdparm kb/sec',
many involving Maxtor drives of various models, but no clear
resolutions.
- Bad drive?
- Bad configuration?
- More data needed? If so, what?
- Other?
Assistance very much appreciated.
Peace.
--------------------
Notes:
1. 149.36 times, if you're doing the math.
--
Karsten M. Self <kmself@ix.netcom.com> http://kmself.home.netcom.com/
What Part of "Gestalt" don't you understand?
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