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* very slow write to AHCI device
@ 2012-05-07 16:16 Daniel Pocock
  2012-05-07 18:10 ` Martin Mokrejs
  0 siblings, 1 reply; 6+ messages in thread
From: Daniel Pocock @ 2012-05-07 16:16 UTC (permalink / raw)
  To: linux-ide



Hi,

I'm testing a problem with the following combination:
- SB700/SB800 type controller in AHCI mode (in a HP Microserver N36L)
- Seagate Barracuda 1TB 7k2 drive with NCQ

I've got a fresh 256MB partition, formatted ext4, mounted
barrier=1,data=ordered, write-cache enabled (hdparm -W 1 /dev/sdb) and
shared over NFS.

When the NFS client writes,
- unpacking a source tarball, many small files, iostat reports speeds
under 500kBytes/sec
- dd conv=fsync, iostat reports about 50MB/sec

If I set up a USB disk on the same box, with a partition formatted
exactly the same way, the iostat reports the write speed (unpacking the
same tarball) is over 5MBytes/sec - not so fast, but 10 times faster
than the AHCI device.

Is there anything I can do to troubleshoot this issue?

Or should I just stop using this onboard SATA and go to something like
an Adaptec 1405?

Regards,

Daniel



^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2012-05-08  8:18 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-05-07 16:16 very slow write to AHCI device Daniel Pocock
2012-05-07 18:10 ` Martin Mokrejs
2012-05-07 18:11   ` Daniel Pocock
2012-05-07 18:27     ` Martin Mokrejs
2012-05-07 23:30       ` Daniel Pocock
2012-05-08  8:21         ` Martin Mokrejs

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