On 07/20/2015 01:17 PM, Jeff Moyer wrote:
<resent with Jens' email address fixed> Hi, This reverts commit 34b48db66e08, which caused significant iozone performance regressions and uncovered a silent data corruption bug in at least one disk. For SAN storage, we've seen initial write and re-write performance drop 25-50% across all I/O sizes. On locally attached storage, we've seen regressions of 40% for all I/O types, but only for I/O sizes larger than 1MB.
Do we have any understanding of where this regression is coming from? Even just basic info like iostats from a run would be useful.
In addition to the performance issues, we've also seen data corruption on one disk/hba combination. See http://marc.info/?l=linux-ide&m=143680539400526&w=2
That's just sucky hardware... That said, it is indeed one of the risks. We had basically the same transition from 255 as max sectors, since we depended on ATA treating 0 == 256 sectors (as per spec).
-- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
