On Fri, Jan 18, 2008 at 11:01:11AM -0800, Martin Knoblauch wrote: > At least, rc1-rc5 have shown that the CCISS system can do well. Now > the question is which part of the system does not cope well with the > larger IO sizes? Is it the CCISS controller, LVM or both. I am open to > suggestions on how to debug that. What is your LVM device configuration? E.g. 'dmsetup table' and 'dmsetup info -c' output. Some configurations lead to large IOs getting split up on the way through device-mapper. See if these patches make any difference: http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/ dm-md-merge_bvec_fn-with-separate-bdev-and-sector.patch dm-introduce-merge_bvec_fn.patch dm-linear-add-merge.patch dm-table-remove-merge_bvec-sector-restriction.patch Alasdair -- agk@xxxxxxxxxx - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
