On 12 April 2011 18:14, Roman Mamedov <rm@xxxxxxxxxx> wrote: > On Tue, 12 Apr 2011 17:56:05 +0100 > Mathias BurÃn <mathias.buren@xxxxxxxxx> wrote: > >> I'm approaching over 6.5TB of data, and with an array this large I'd >> like to migrate to RAID6 for a bit more safety. > > That's a great decision (and I suppose you made a typo in the subject). > RAID5 is downright dangerous at that disk count, and with disks of that size. > >> I'm just checking if I >> understand this correctly, this is how to do it: >> >> * Add a HDD to the array as a hot spare: >> mdadm --manage /dev/md0 --add /dev/sdh1 >> >> * Migrate the array to RAID6: >> mdadm --grow /dev/md0 --raid-devices 7 --level 6 > > Looks correct to me... > > The first command can be just "mdadm --add /dev/md0 /dev/sdh1". > > If you'd rather avoid a reshape at this point, you can add > "--layout=preserve" to the second line. That way you will have just a rebuild > of the new drive, instead of a full reshape. > > You will also need to "--grow --bitmap=none" first (you can re-add the bitmap > later). > > -- > With respect, > Roman > Hi, Yep I mean RAID6, stupid subject line. If I use --layout=preserve , what impact will that have? Will the array have redundancy during the rebuild of the new drive? If I preserve the layout, what is the final result of the array compared to not preserving it? Cheers, // Mathias -- 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
