i slowly learn software RAID things, and now i get on the backup disc creation problem.
i have a raid 1 from two identical drives, and try to "clone" one of disc with thing, if i get that "cloned" ( backup version of my raid) disc on new computer, get one the same spare disc, then i can get up all my raid with all info on it.
as so i put third disc on machine with working raid1 from two discs ( slackware64 14.1 if that matter), as /dev/sdc ( raid discs is respectively, sda and sdb.)
i copy primary raid disc to spare disc with dd:
dd if=/dev/sda of=/dev/sdc bs=1M
when all copied, i shut down machine, remove both "old", raid discs ( sda and sdb) and put there that sdc where i copied data - as sda, and put there also one new identical empty disc as sdb, for restore a raid.
but there i encounter a problems - when i make first raid, i use --metadata=0.90 only for first raid partition - /md1 - which is bootable and root. md2 (swap) and md3 ( /second) maked without --metadata and thus it have ?superblock ver 1.2? not 0.9
when i start in new configuration, i get a many messages, and only my md1 partition \ raid start up and mount.
looks like it not right way to make raid backup
i suppose, better be a clone raid via grow source raid from 2 devices to 3, wait to synchronize all, and then someway shrink raid from 3 to 2 devices, and get new spare disc out?
maybe there is anyone with experience and knowledge in that field?
thanks in advice....
P.S. mostly i build entire RAID 1 based on this manual:
except, as i say, i define --metadata=0.90 only for first partition raid, not for all.