Re: Awful RAID5 random read performance

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Wil Reichert wrote:
On Mon, Jun 1, 2009 at 5:43 AM, Maurice Hilarius <maurice@xxxxxxxxxxxx> wrote:
Thomas Fjellstrom wrote:
..
Yet I've heard NCQ makes some things worse. Some raid tweaking pages tell
you to try disabling NCQ.

Not so relevant here.
This recommendation to  disable drive NCQ is generally due tot he fact that
NCQ implementations by various manufacturers tend
to differ in behaviour, and, in some cases , is just plain "broken".

Not trying to start a flamewar on whos hardware is better, but I'd
love to get clarification on that last statement.  I've always been
under the impression Intel gets their NCQ right (works for me).  All
the reviews I've read on the current set of AMD southbridges indicate
they don't but I've no personal experience there.  No idea about
nvidia or the cheap add-in sata cards like Silicon Image.

Wil
From speaking with hardware RAID card manufacturers support engineers over the past few years, there have been several instances where NCQ implementations were incomplete, or faulty, or both.

This seems to have improved a lot over the last year or two, so I think it is likely now "OK".

However, from the earlier history I think there is a tendency for people now to assume it is "broken",
and to turn it off.


--
Regards, Maurice
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux RAID Wiki]     [ATA RAID]     [Linux SCSI Target Infrastructure]     [Linux Block]     [Linux IDE]     [Linux SCSI]     [Linux Hams]     [Device Mapper]     [Device Mapper Cryptographics]     [Kernel]     [Linux Admin]     [Linux Net]     [GFS]     [RPM]     [git]     [Yosemite Forum]


  Powered by Linux