replication, how to see if it 'up to date'

[Rudy Gevaert]

Hi Bron!

Bron Gondwana wrote:

> Our monitoring script that runs every 2 minutes does a "du -s" on the
> {configdirectory}/sync directory and notifies us if it gets "big" (where
> big is obviously a per-instance variable)
> 
> A less frequently run script searches the ps output for copies of
> sync_client.  It then looks in they sync directory, and for any
> file called log-{N} it checks if there is a sync_client with PID
> {N}.  If not, it tries to run it with -r -f.  Finally, if there
> was no sync_client at all, it launches a new one with -r.

Interesting.  So running the syn_client with -r -f file let it catch up?

> Thirdly we have a tool which makes an imap connection to each of
> the master and replica (we run an imapd on a different port on the
> replica purely for this purpose) and does a bunch of checks
> on each mailbox.  It has to run as each user to get SEEN state.
> This script has multiple levels of test, right up to one that
> actually randomly picks a few messages and fetches their bodies
> for comparison.  It always checks at least flags and everything
> you can STATUS for.  This tool also has an optional flag which
> can ssh to the apropriate servers and run reconstruct on the
> mailboxes as well as sync_client -u on the offending user if it
> finds inconsistencies.  Obviously, there's a possibility that
> it catches changes where sync_client just hasn't caught up yet,
> but it retries multiple times with a tunable delay, so generally
> it will get the same value on one of the retries unless the
> folder is seeing a lot of traffic.

Also very interesting!

Thanks in advance!

-- 
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Rudy Gevaert          Rudy.Gevaert at UGent.be          tel:+32 9 264 4734
Directie ICT, afd. Infrastructuur  Direction ICT, Infrastructure dept.
Groep Systemen                     Systems group
Universiteit Gent                  Ghent University
Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
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