On 31/08/2011 13:30, Paul Clements wrote:
On Wed, Aug 31, 2011 at 5:05 AM, CoolCold<coolthecold@xxxxxxxxx> wrote:
root@gamma2:~# cat /proc/mdstat
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md3 : active raid1 sdc3[1] sdb3[0]
1443552640 blocks [2/2] [UU]
bitmap: 16/22 pages [64KB], 32768KB chunk
More details now:
Array still has 16/22 dirty pages:
root@gamma2:~# mdadm --examine-bitmap /dev/sdc3
Sync Size : 1443552640 (1376.68 GiB 1478.20 GB)
Bitmap : 44054 bits (chunks), 189 dirty (0.4%)
But only 189 bits dirty. This means the bits are just distributed
across the disk (which is why you have 16/22 pages dirty).
Any activity on the disk? 189 bits could easily be explained by a
small amount of background disk activity on a disk that big.
That makes sense to me. I have:
$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [raid1]
md1 : active raid6 sde2[4] sdd2[3] sdc2[2] sdb2[1] sda2[0]
2929966080 blocks level 6, 512k chunk, algorithm 2 [5/5] [UUUUU]
bitmap: 2/4 pages [8KB], 131072KB chunk
Oh no! Half my array is dirty! But then:
# mdadm --examine-bitmap /dev/sdb2
Filename : /dev/sdb2
Magic : 6d746962
Version : 4
UUID : d8c57a89:166ee722:23adec48:1574b5fc
Events : 1338800
Events Cleared : 1338800
State : OK
Chunksize : 128 MB
Daemon : 5s flush period
Write Mode : Normal
Sync Size : 976655360 (931.41 GiB 1000.10 GB)
Bitmap : 7452 bits (chunks), 7 dirty (0.1%)
Not so bad after all.
On the other hand, repeatedly checking /proc/mdstat shows different
numbers of pages being dirty, and --examine-bitmap shows different
numbers of bits being dirty each time, whereas CoolCold managed 16 pages
repeatedly and 189 bits being dirty twice in a row. CoolCold, please can
you test --examine-bitmap again several times at least 5 seconds apart?
Cheers,
John.
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