[Samba] Restoring Samba databases from /var/lib/samba
robert at marcanoonline.com
Thu Jun 2 14:58:07 UTC 2022
On 6/1/22 5:54 PM, Sebastian Arcus via samba wrote:
> To start with the end, until today I never realised that there are
> specific procedures for backing up Samba AD databases - which is my bad.
> I've always backed up /var/lib/samba and /var/cache/samba, seeing as
> that's where Samba kept its stuff. Today I've accidentally deleted
> /var/lib/samba, and tried to copy it back from the nightly backups.
> Needless to say that it all went to pots, and dns is not working
> properly any more, not matter what I try. I can provide more details and
> logs, but first I wanted to ask if it is even worth the effort? Is my
> backup of /var/lib/samba basically useless to restore things to where
> they were before?
I have never had a problem moving Samba DCs from one node to another,
with file copying, without using Samba backup features or demoting and
adding a new DC. I run them as containers, so all the state in
/var/lib/samba is properly isolated from the rest of the system.
What you must take into account is:
1) Backup ACLs and entire list of Extended Attributes, specially the
Samba specific ones (this is for SYSVOL permissions)
2) Use a filesystem snapshot so the state is backed up intact, If the Dc
is running at the time of the backup it will be restored as a crashed
instance. You can stop, make the snapshot start inmediatly and then make
the backup of the snapshot.
3) Or you can stop it and make a backup without a snaphot and later
So your problem maybe complex because you may have database
inconsistencies caused by how the backup was made lik,e files being
modified while being bnacked up.
> Some basic info:
> OS: Slackware 14.1
> Samba: 4.9.4
> Mode: Active Directory DC with file server on the same machine - only
> one DC on domain
> Briefly, the samba_dlz plugin seems to be loading, but the logs have
> various errors which so far I can't make sense of:
> Jun 1 22:36:05 srv-01-op samba:
> ../source4/dsdb/kcc/kcc_periodic.c:768: Failed samba_kcc -
> # samba-tool dns zonelist localhost -U Administrator
> Password for [redacted\Administrator]:
> ERROR(runtime): uncaught exception - (9717,
> File "/usr/lib64/python2.7/site-packages/samba/netcmd/__init__.py",
> line 177, in _run
> return self.run(*args, **kwargs)
> File "/usr/lib64/python2.7/site-packages/samba/netcmd/dns.py", line
> 670, in run
> Should I just cut my loses and rebuild everything from scratch? It will
> involve work from my part and downtime for the users, but I should have
> really known about proper Samba AD db backups, so it is what it is.
> Any pointers much appreciated.
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