Thanks for the reply. Sadly, this specific server is 150 miles away in colo, and only has a single on-board controller (it's a Dell R310). I'd be surprised if it was controller/contention related, but I certainly won't rule it out. Cal On Tue, Jul 5, 2011 at 1:34 AM, NeilBrown <neilb@xxxxxxx> wrote: > On Sat, 2 Jul 2011 12:07:54 +0100 "Cal Leeming [Simplicity Media Ltd]" > <cal.leeming@xxxxxxxxxxxxxxxxxxxxxxxx> wrote: > >> Hi all, >> >> I tried to rebuild/sync two RAID1 arrays at the same time, with strange results. >> >> When a new drive was added into md0, it started to sync fine at >> 123,000kb/sec. Whilst that was running, I also added a new drive into >> md1, and this causes both arrays sync speed to slow down to >> 20,000kb/sec. I checked the /proc/sys/dev/raid/speed_limit_{min|max} >> and these were both set fine. >> >> I removed the drive from md1, and the md0 sync went back to the normal speed. >> >> RAID Setup: >> md0 - 2 drives (2TB Western Digital) >> md1 - 2 drives (500GB M3 SDD) >> >> So my question is, does anyone know why the sync speed (on all arrays) >> slowed down to almost 6-7 times the norm, when two (or more?) sync >> operations are taking place? >> > > Dodgy controller? I assume both arrays are on the same controller. > > Can you plug in a separate controller even if only temporarily and see what > happens? > > I can see how any interaction with md would have this effect. > > NeilBrown > > -- 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