Re: MD: Feature Request: Estimate of blocks necessary to complete sync

On Thursday December 11, jnelson-linux-raid@jamponi.net wrote:

When one is using a bitmap-enabled raid1 (or raid5 or whatever), MD
prints messages like this to the kernel log when a previously-used
device is re-added:


Dec 11 08:59:40 turnip kernel: md: recovery of RAID array md10
Dec 11 08:59:40 turnip kernel: md: minimum _guaranteed_  speed: 1000
KB/sec/disk.
Dec 11 08:59:40 turnip kernel: md: using maximum available idle IO
bandwidth (but not more than 200000 KB/sec) for recovery.
Dec 11 08:59:40 turnip kernel: md: using 128k window, over a total of
78123968 blocks.
Dec 11 08:59:41 turnip nbd0-frank: mdadm: /dev/nbd0 attached to
/dev/md10 which is already active.
Dec 11 09:00:22 turnip kernel: md: md10: recovery done.

What would be nice is the addition of something like this:
Dec 11 08:59:40 turnip kernel: md: bitmap shows 27 128K blocks requiring sync
or
Dec 11 08:59:40 turnip kernel: md: bitmap shows 3456K blocks requiring sync
or some other analogue.

Seem reasonable?

Probably.  I wouldn't be too hard to could the number of bits that are
set.  I guess it could be useful.

I'll put it on my list :-)
NeilBrown