Re: 2.6.17-mm4 raid bugs & traces

[Helge Hafting <helgehaf@aitel.hist.no>]

On Sun, Jul 02, 2006 at 05:38:40PM +1200, Reuben Farrelly wrote:
> On 2/07/2006 4:25 a.m., Helge Hafting wrote:
> >More mm4 raid-1 troubles.
> 
> >More than a little irritating, I need the SATA raid-1 to be in sync
> >so lilo can install mm5 for me. 18 hours. 
> 
> Have you looked at enabling write-intent bitmaps on your raid-1 arrays?
> 
Didn't know about those. I solved this by rebooting into
2.6.16-rc6-mm2, where the resync is one hour.  2.6.15 must have bad
SATA drivers.
> With all the grief I have been having with RAID-1 recently, bitmaps have 
> saved me very very serious amounts of time resyncing the array.
> 
> Typically after my raid array has had devices/partitions kicked out (such 
> as when loading -mm5) it takes only 2-3 seconds to bring each non-fresh 
> device/partition back into the array and back up to sync (as opposed to 18 
> hours...).
> 
> Neil wrote a good posting at http://lkml.org/lkml/2005/12/4/118 about it 
> (which should be a FAQ entry in itself).

Thanks for the tip. I now have write intent bitmaps enabled on all
my arrays.

Helge Hafitng