On Mon, Dec 5, 2011 at 7:11 AM, NeilBrown <neilb@xxxxxxx> wrote:
> 5 seconds suggests a bitmap update. Do you have an internal bitmap?
I don't, but I enabled it on those arrays before with default delay.
I then removed it when I suspected (with help of block_dump) it to
cause spin-ups, and I noticed an improvement. Recently, the machine
was restarted (once on 3.0 kernel, and again to update to 3.1), and
after both restarts those 5s periodic writes occurred.
> Then try adding it back with a longer delay
> mdadm --grow /dev/md0 --bitmap=internal --delay=60
Adding bitmaps on both arrays (md0 and md1), 5s periodic writes disappear.
Removing bitmaps seems to preserve the improvement.
Could the delay setting have survived on-disk and be used when
initializing the array, but cleared when mdadm later disables bitmap
usage ?
> What kernel version are you running?
3.1.4, according to dpkg:
ii linux-image-3.1.0-1-amd64 3.1.4-1
Linux 3.1 for 64-bit PCs
Regards,
--
Vincent Pelletier
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