I'm new to RAID. Creating a new RAID1 array from blank, newly-partitioned 100GB disks with
sudo mdadm --create --verbose /dev/md0 --level=mirror --raid-devices=2 /dev/xvdf1 /dev/xvdg1
...looks to be taking about an hour to rebuild. My questions are:
are there any shortcuts that can be taken on this initial "resync", since there's not (AFAIK) any data I need copied between the empty disks
can I blithely format
/dev/md0
and treat it like a normal disk while it's in the middle of its initial sync, as long as I'm okay with it being in a "degraded" state for a bit?
I don't know about a shortcut, but you can start to use it immediately, with a reduced performance as only drawback.
See the mdadm manpage for drawbacks.