On 07/08/16 01:32, Glenn Enright wrote: > On 7/08/2016 12:01 pm, "Wols Lists" <antlists@xxxxxxxxxxxxxxx > <mailto:antlists@xxxxxxxxxxxxxxx>> wrote: >> >> On 05/08/16 21:16, Wols Lists wrote: >> > In my testing of xosview, I've been mucking about with a vm and raid. >> > xosview is looking quite promising (I've got a few comments about it, >> > but never mind). >> > >> > BUT. In mucking about with raid 1, I increased my raid devices to three. >> > I now just can NOT convert the array to raid 5! I've been mucking around >> > with all sorts of things trying to get it to work, but finally two error >> > messages make things clear. >> > >> Following up to myself - suddenly thought "I know what's wrong". So I >> stopped the array, and of course couldn't access it, it was no longer >> there. So I assembled but didn't run it, and it worked fine. >> >> Simples, once you realise what's wrong - you can ADD devices to a >> running array, but you can't REMOVE them. >> >> Cheers, >> Wol >> > > You can remove em if you mark em as failed first. Eg > > Mdadm /dev/mdx --fail /dev/sdc1 --remove /dev/sdc1 > > Best, Glenn > Except - if you read my original post - I was trying to TOTALLY remove the device! mdadm --grow -raid-devices=2 THAT was the problem - I had a 3-device mirror, and you can't convert that to raid5! Even if you've --fail --remove'd the third device! In other words, "--grow --raid-devices=more" will work on a running device, "--grow --raid-devices=less" will only work on an array that is built but not running. I now have the problem that my "--grow --level=5" has fallen foul of the "reshape stuck at zero" problem, and I can now neither run the array, nor get the reshape working ... :-( At least it's a test vm, specifically for mucking about with raid, so if I trash it all and start again it's no loss, but it's worrying if a reshape threatens to lose all your data for you! Especially as I intend to do it live at some point! Cheers, Wol -- 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
