md bitmaps on 2.6.16.y

md bitmaps on 2.6.16.y

[Ed L. Cashin]

I have been testing an md RAID 1 created using mdadm 2.6.1 on a
2.6.16.35 kernel, and the initial results are encouraging.  (The
2.6.16.y kernel is a long-term stable branch, unlike most stable
kernels, which are maintained only until the next stable branch
becomes active.)

I see bitmap-related patches with fixes for later kernels being
discussed in the linux-raid mailing list, but I do not see
bitmap-related patches in the ChangeLogs for the 2.6.16.y kernel.  My
hope is that these fixes are only part of the natural churn in the
newer kernel branches and are not needed for the 2.6.16.y kernels.

Are there any known issues that would make the use of md bitmaps in a
2.6.16.y kernel problematic?  I do see an important RAID 1 fix in
2.6.16.40, so I know that 2.6.16.35 isn't good enough.

-- 
  Ed L Cashin <ecashin@coraid.com>

Re: md bitmaps on 2.6.16.y

[Neil Brown]

On Monday March 26, ecashin@coraid.com wrote:
> I have been testing an md RAID 1 created using mdadm 2.6.1 on a
> 2.6.16.35 kernel, and the initial results are encouraging.  (The
> 2.6.16.y kernel is a long-term stable branch, unlike most stable
> kernels, which are maintained only until the next stable branch
> becomes active.)
> 
> I see bitmap-related patches with fixes for later kernels being
> discussed in the linux-raid mailing list, but I do not see
> bitmap-related patches in the ChangeLogs for the 2.6.16.y kernel.  My
> hope is that these fixes are only part of the natural churn in the
> newer kernel branches and are not needed for the 2.6.16.y kernels.
> 
> Are there any known issues that would make the use of md bitmaps in a
> 2.6.16.y kernel problematic?  I do see an important RAID 1 fix in
> 2.6.16.40, so I know that 2.6.16.35 isn't good enough.


While I try to remember to back-port any significant and relevant
bugfixes to 2.6.16, I do forget sometimes.. and 2.6.16 isn't really my
focus of development.

If you would like to generate a list of bitmap bugfixes in later
kernels, I could check and let you know how relevant they are for
2.6.16.

NeilBrown