Re: dirty chunks on bitmap not clearing (RAID1)

["NeilBrown" <neilb@suse.de>]

On Thu, October 15, 2009 9:39 am, aristizb@ualberta.ca wrote:
> Hello,
>
> I have a RAID1 with 2 LVM disks and I am running into a strange
> situation where having the 2 disks connected to the array the bitmap
> never clears the dirty chunks.

That shouldn't happen...
What versions of mdadm and the Linux kernel are you using?

NeilBrown

>
> I am assuming also that when a RAID1 is in write-through mode, the
> bitmap  indicates that all the data has made it to all the disks if
> there are no dirty chunks using mdadm --examine-bitmap.
>
> The output of cat /proc/mdstat is:
>
> md2060 : active raid1 dm-5[1] dm-6[0]
>        2252736 blocks [2/2] [UU]
>        bitmap: 1/275 pages [12KB], 4KB chunk, file: /tmp/md2060bm
>
>
> The output of mdadm --examine-bitmap /tmp/md2060bm is:
>
> Filename : md2060bm
>             Magic : 6d746962
>           Version : 4
>              UUID : ad5fb74c:bb1c654a:087b2595:8a5d04a9
>            Events : 12
>    Events Cleared : 12
>             State : OK
>         Chunksize : 4 KB
>            Daemon : 5s flush period
>        Write Mode : Normal
>         Sync Size : 2252736 (2.15 GiB 2.31 GB)
>            Bitmap : 563184 bits (chunks), 3 dirty (0.0%)
>
>
> Having the array under no IO, I waited 30 minutes but the dirty data
> never gets clear from the bitmap, so I presume  the disks are not in
> sync; but after I ran a block by block comparison of the two devices I
> found that they are equal.
>
> The superblocks and the external bitmap tell me that all the events
> are cleared, so I am confused on why the bitmap never goes to 0 dirty
> chunks.
>
> How can I tell if the disks are in sync?
>
>
> Thank you in advance for any help.
>
>
> --
> Juan Aristizabal
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