Re: Internal bitmap always 1/1

[John Robinson <john.robinson@anonymous.org.uk>]

On 04/01/2011 16:51, Andrea Gelmini wrote:
> Hi all,
>     and thanks a lot for your effort on MdAdm.
>     With latest git version of mdadm tools¹ I have
>     problems with creation of internal bitmap. Doing something like this:
>     ./mdadm -Ss;./mdadm --create /dev/md0 --level=1 --raid-devices=2
> --assume-clean --bitmap=internal /dev/sdb5 missing --auto=md -e
> 1.2;cat /proc/mdstat
>     mdadm: stopped /dev/md0
>     mdadm: /dev/sdb5 appears to be part of a raid array:
>        level=raid1 devices=2 ctime=Tue Jan  4 17:29:06 2011
>     Continue creating array? y
>     mdadm: array /dev/md0 started.
>     Personalities : [linear] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
>     md0 : active raid1 sdb5[0]
>        55777208 blocks super 1.2 [2/1] [U_]
>        bitmap: 1/1 pages [4KB], 65536KB chunk
>
>      I always have 1/1 pages (also with different partition sizes: 1G
> as 80G, no differences).

Why is this a problem? Your bitmap is simply too small to need more than 
one page, whether it's a 1G or 80G. With a 16MB bitmap chunk size on a 
2TB array I have 2 pages.

If you want to see how busy the bitmap is, try `mdadm --examine-bitmap 
/dev/component`

Cheers,

John.

--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html