On Mon, May 30, 2011 at 12:40:39PM -0400, Mikulas Patocka wrote: > Here I'm sending three patches that limit kcopyd speed. There is global > limit for all kcopyds running in a system. The user can set percentage of > kcopyd speed in /sys/module/dm_mod/parameters/dm_kcopyd_throttle Could you give some explanation of how to choose an appropriate value for this please? Should it be 100% unless there is an issue? How does the sys admin spot such issues? Different kcopyd clients have different performance requirements, for instance the initial sync of a new mirror leg may have less priority than a copy-on-write exception for a snapshot. This isn't something we've addressed so far, but if you're starting to slow kcopyd down (i.e. so the mirror sync doesn't saturate the system), then I think you'll get some complaints from the snapshot users. - joe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
