Re: Hi! Strange issue with LSR -- bitmaps hadn't been used during 2 of 3 RAIDs resync

[Igor M Podlesny <for.poige+lsr@xxxxxxxxx>]

On 26 June 2012 14:18, NeilBrown <neilb@xxxxxxx> wrote:
> On Wed, 20 Jun 2012 10:49:32 +0800 Igor M Podlesny <for.poige+lsr@xxxxxxxxx>
> wrote:
[…]
>>    Here it is: http://pastie.org/4118133
>
> This doesn't appear to show the "start to end" that I suggested, just 10% to
> 30%, but it does suggest that the bitmap isn't speeding things up at all, at
> least for that part of the array... That is assuming you are talking about

   Well, I decided that's enough to be "pasted", but anyway, I can
assure you — it took ~ 1 hour, as it was estimated, so yeah — no use
of bitmap. For sure.

> md124.  I note that md125 doesn't have a bitmap.  Is that what you are
> referring to?

   Yeah, md125 is legacy RAID which is not being in use for a long
time, it's just hanging around till re-layout happens.
>
> The next thing to do would be to look at the bitmap immediately after reboot
> to see how many bits are set.  Maybe lots are set for some reason.
>
>>
>>    — 3.4.2-rt10 went suspend ok for 2 times, the 3rd it didn't.
>> Reboot, resync, no bitmaps use.
>>
>>    And, BTW, it's rather slow in despite of having max. stripe_cache_size set.
>>
>
> A larger stripe cache isn't going to affect resync speed much (I think).
> 50MB/sec on each drive seems fairly good to me.  What were you expecting?

   I see, thanks.

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