Re: raw aio write guarantee

From: Kyle Moffett
Date: Wed Sep 28 2005 - 15:13:52 EST


On Sep 28, 2005, at 12:42:50, iodophlymiaelo@xxxxxxxxx wrote:
Erm, is the hardware problem really as great as you're implying? Have you personally encountered any bad drives made by reputable brands? Mostly I've only heard only of people crying wolf and then realizing it was a problem with their reasoning or with the assumption that fsync() actually works properly on kernel X, where X doesn't even have to be that ancient a version of linux ;-)

No, I've seen several sample cases on this list of drives where the IDE or SCSI cache flush commands did not trigger any disk activity and the only way to force it out of the cache was to write several meg of garbage to some file. In some cases (Like RAID cards with good battery backup, for example), they may ignore the flush cache command as it isn't really useful (although on such good cards, they usually haw a way to turn it off, too).

Cheers,
Kyle Moffett

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GCM/CS/IT/U d- s++: a18 C++++>$ UB/L/X/*++++(+)>$ P+++(++++)>$ L++++(+ ++) E W++(+) N+++(++) o? K? w--- O? M++ V? PS+() PE+(-) Y+ PGP+++ t+(+ ++) 5 X R? tv-(--) b++++(++) DI+ D+ G e->++++$ h!*()>++$ r !y?(-)
------END GEEK CODE BLOCK------


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/