On Monday June 11, davidsen@xxxxxxx wrote: > Jan Engelhardt wrote: > > Hi, > > > > > > RAID levels 0 and 4 do not seem to like the -b internal. Is this > > intentional? Runs 2.6.20.2 on i586. > > (BTW, do you already have a PAGE_SIZE=8K fix?) > > > > 14:47 ichi:/dev # mdadm -C /dev/md0 -l 4 -e 1.0 -b internal -n 2 /dev/ram[01] > > mdadm: RUN_ARRAY failed: Input/output error > > mdadm: stopped /dev/md0 > > 14:47 ichi:/dev # mdadm -C /dev/md0 -l 0 -e 1.0 -b internal -n 2 /dev/ram[01] > > mdadm: RUN_ARRAY failed: Cannot allocate memory > > mdadm: stopped /dev/md0 > > > > Right... md: bitmaps not supported for this level. > > > > Bitmaps show what data has been modified but not written. For RAID-0 > there is no copy, therefore there can be no bitmap to show what "still > needs to be updated." I would have thought that RAID-4 would support > bitmaps, but maybe it was just never added because use of RAID-4 is > pretty uncommon. "added late" rather than "never added". 2.6.21 supports bitmaps on RAID-4, The patch is about 2 lines and would apply to 2.6.20 with no trouble. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=3d37890baa4ca962f8a6b77525b8f3d0698eee09 > > BTW: RAID-4 seems to work fine with an external bitmap. Were you trying > to do "internal?" I suspect you were using 2.6.21-rc6 or later? NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
