Hi, >> That's a good argument for not using "whole disk" array members, a partition can >> be started at a good offset and may perform better. As for the speed, since it >> is reconstructing the array data (hope the other drives are okay), every block >> written requires three blocks read and a reconstruct in cpu and memory. You can >> use "blockdev" to increase readahead, and set the devices to use the deadline >> scheduler, that _may_ improve things somewhat, but you have to read three block >> to write one, so it's not going to be fast. >> > > Read-ahead has absolutely no effect in this context. > > Read-ahead is a function of the page cache. When filling the page cache, > read-ahead suggests how much more to be read than has been asked for. > > resync/recovery does not use the page cache, consequently the readahead > setting is irrelevant. > > IO scheduler choice may make a difference. It's already set for cfq. I assume that would be the preferred over deadline? I set it on the actual disk devices. Should I also set it on md0/1 devices as well? It is currently 'none'. /sys/devices/virtual/block/md0/queue/scheduler Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
