Scenario: My home dir is on NFS, identities are in LDAP and authorization is via Kerberos. My NFS, LDAP and Kerberos servers are all VMs -- I'm stretching a little hardware a long way at home.
Life is Good ... until -- there's always an until -- my VM server down for maintenance (planned or worse) which then strips me of lots of conveniences for the maintenance/repair work.
For clarity here: $HOME and $USER are the normal, real ones while $CHOME and $CUSER are the local clones.
Option 1: rsync -av $HOME/ $CHOME/ Easy, but while sssd will cache my credentials for the offline period $USER points to $HOME (which is inaccessible) and not $CHOME.
Option 2: Similar but make $CHOME owned by $CUSER instead. Now $USER is denied access to $CHOME or, alternatively $CUSER is denied access $HOME. I can't use root because $HOME is exported with root_squash and I'd like to keep it that way.
Option 3: Like option 2 but use ACLs somehow. Shouldn't I be able to setfacl default ACLs on $CHOME before the first rsync and have them survive? Everything I've tried requires setfacl -R $CHOME again after each rsync and that seems like I'm just doing something wrong.
I really only need the one-way replication, but the best solution would be something like Unison so that this could move beyond a simple recovery/maintenance aid to also support our laptop using NFS while online at home but operating normally while offline.