[CentOS] Convert "bare partition" to RAID1 / mdadm?

Wed Jul 30 00:40:22 UTC 2014
Benjamin Smith <lists at benjamindsmith.com>

On 07/28/2014 05:02 PM, Cliff Pratt wrote:
> 1. Setup inotify (no idea how it would behave with your millions of files)
> >
> >2. One big rsync
> >3. Bring it down and copy the few modified files reported by inotify.
> >
> >Or lsyncd?

lsyncd is interesting, but for our use case isn't nearly as efficient as 
ZFS with send/receive. For one case, lsyncd is only useful after the 
first rsync (which in this case is days) so we would effectively start 
out with an out-of-sync system and then have to deal with millions of 
follow up syncs as the monstrous number of queued up inotify events get 
handled.

I'm moving ahead with the rsync-a-few-directories-at-a-time method Jerry 
Franz put forward, as it's fundamentally compatible with our setup. (Our 
"Subdir" is called a "client" - we have hundreds - and we do that during 
off-hours that clients' business is closed, so nobody notices) But It 
takes a week or two to fully resync a file store... in the meantime 
we're at N+1 redundancy instead of N+2 as usual.