On 6/16/2010 11:52 AM, Bill Davidsen wrote: > Not sure what's causing that, other than you just have your max set > pretty high for raid1. 200000 is just the default. > By leaving nothing in the way of capacity for > system operation you are filling all of memory with writes to the > resyncing drive. I would measure the speed of the disk read on the inner > tracks (dd with offset from sda to /dev/null) and not set max over 2/3 > of that. The outer tracks measure about 65000 KB/sec, and the inner tracks about 35000 KB/sec. The problem I have with just setting sync_speed_max to a fixed, low value like 30000 prior to starting the data-check is it needlessly slows down the reading of the outer tracks, causing the check to take an extra hour or so to complete. I would prefer to see md use as much bandwidth as possible, but pause whenever any I/O requests come in. This appears to be what the code is designed to do -- and the log says "idle IO bandwidth" -- but given that tasks are routinely hanging for 120+ seconds, it doesn't seem to be working in my case. > Alternatively, you can try setting your io scheduler to > deadline, Interesting idea. I'll give that a try and report back. > I think md would benefit from a limit on how much io can be outstanding > to any given device, but that would be a non-trivial change, I fear. Perhaps an option to force msleep()s at regular intervals (e.g., every 50 MB) would help... -- Jordan Russell -- 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
