>>>> I have a 4 drive array with 1 TB Hitachi disks, formatted >>>> as raid10,f2 I had some strange observations: 1. while >>>> resyncing I could get the raid to give me about 320 MB/s in >>>> sequential read, which was good. After resync had been >>>> done, and with all 4 drives active, I only get 115 MB/s. [ ... ] >> Is this with, or without, your patch to avoid "read-balancing" >> for raid10/far layouts? It sounds like it is without that >> patch ???? > I tried both without the patch and with the patch, with almost > same resulte. That could be the usual issue with apparent pauses in the stream of IO requests to the array component devices, with the usual workaround of trying 'blockdev --setra 65536 /dev/mdN' and see if sequential reads improve. > Is resync building some table, and could that be it? Or could > it be some time of inode traffic? One good way to see what is actually happening is to use either 'watch iostat -k 1 2' and look at the load on the individual MD array component devices, or use 'sysctl vm/block_dump=1' and look at the addresses being read or written. -- 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
