Making Replication Robust

[David Carter]

On Mon, 8 Oct 2007, Bron Gondwana wrote:

> We already run a sync_server on our masters as well because we use it 
> for user moves:
>
> Generally takes about 15 seconds for the "critical path" bit, and
> the initial sync doesn't matter how long it takes.

As do we. In fact when I first showed the replication system to Rob 
Siemborski (few a years back now), he was thinking about using replication 
to replace XFER in a murder environment.

I have a special "-y" flag to sync_client which disables fsync() on the 
replica for fast seeding of replicas. We also use replication to dump data 
from the live systems to a tape spooling array each night. Replication is 
transaction safe rsync for Cyrus, tailored around the cyrus.index files.

More later.

-- 
David Carter                             Email: David.Carter at ucs.cam.ac.uk
University Computing Service,            Phone: (01223) 334502
New Museums Site, Pembroke Street,       Fax:   (01223) 334679
Cambridge UK. CB2 3QH.