Re: libata FUA revisited

From: Robert Hancock
Date: Wed Feb 21 2007 - 09:07:35 EST

Tejun Heo wrote:
Aside from the issue above, as I mentioned elsewhere, lots of NCQ drives
don't support non-NCQ FUA writes..

To me, using the NCQ FUA bit on such drives doesn't seem to be a good
idea. Maybe I'm just too chicken but it's not like we can gain a lot
from doing FUA at this point. Are there a lot of drives which support
NCQ but not FUA opcodes?

Well, it's hard to say whether "lots" have this issue, but the ones I have in my machine, Seagate 7200.7 NCQ 160GB (ST3160827AS) and 7200.10 320GB (ST3320620AS), both support NCQ and don't support non-NCQ FUA, and those (especially the latter) seem to be very popular models.

Likely Seagate didn't implement that command since they figured nobody would use that if they had NCQ..

Robert Hancock Saskatoon, SK, Canada
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