* Jim Nasby (jim.na...@bluetreble.com) wrote: > On 8/17/16 9:46 PM, Stephen Frost wrote: > >* Jim Nasby (jim.na...@bluetreble.com) wrote: > >>> https://wiki.postgresql.org/wiki/Binary_Replication_Tutorial does > >>> not specify -c for any of the rsync commands. That's maybe safe for > >>> WAL, but I don't think it's safe for any of the other uses, right? > >>> I'd like someone to confirm before I just change the page... my > >>> intention is to just stick -c in all the commands. > >-c is only relevant when you are doing an incremental copy, but on a > >quick look, all those rsync commands appear to be doing full copies? > > > >You would want -c if you were taking a backup and then doing an update > >of it using rsync. or something along those lines, as you can't really > >trust rsync's time/size based comparison as it only has a 1 second level > >granularity. > > I don't think it's any great leap for someone to think they can use > those commands incrementally. It's certainly one of the first things > you think of when using rsync. AFAIK there's no downside at all to > using -c when it is a brand new copy, so I'm thinking we should just > put it in there, especially considering what the potential downside > is.
To have proper incremental backups done requires a lot more than just throwing "-c" into the rsyncs. For my 2c, I'm at the point where I'd prefer we discourage people from using rsync, cp, or generally try to set up their own hand-rolled backup system with PG. Those examples simply encourage poor setups that risk losing data and introducing corruption. Thanks! Stephen
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