On Mon, Feb 25, 2002 at 08:58:17AM +1100, Neil Brown wrote: > On Saturday February 23, asmith@umdgrb.umd.edu wrote: > > > Not very.... but what filesystem are you usinf over your RAID5 array? > > > XFS? > > I use ext3. Do you know what causes these errors? > > Yes. > The message (it isn't really an error) indicated that the raid5 layer > got a request for a sector when it already had a pending request for > that sector. This tends to suggest that something odd is going on > with caching somewhere higher up. Normally if a particular block on > disc had been requested and it was wanted again, the fact that a > request was already pending would be noticed and it would not be > repeated. EXT3 (and EXT2) do speed-optimization for "read ahead", which works by asking for disk blocks to be read _without_ waiting for it. IF the data read becomes real (vs. speculative) soon enough (fast reader), the FS code will request the block again, and then wait for it. Could the RAID layer recognize this ? ... > NeilBrown /Matti Aarnio - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
