Re: Cold backup with rsync -- WAL files?

I think it's time to understand/clarify problem before arguing further !!

Craig,

Would you please clarify which of these files you want to ignore in using
cold backup ?
1. WAL files (copied using archive_command to different location)
2. Files under pg_xlog

I assumed you meant #1.

On Fri, Dec 6, 2013 at 4:46 PM, Kevin Grittner <kgrittn(at)ymail(dot)com> wrote:

> Denish Patel <denish(at)omniti(dot)com> wrote:
> > Craig James <cjames(at)emolecules(dot)com> wrote:
> >> Jeff Frost <jeff(at)pgexperts(dot)com> wrote:
> >>>> Craig James <cjames(at)emolecules(dot)com> wrote:
> >>>>
> >>>> After I rsync the postgres data directory, do I need the WAL
> >>>> files from the source (they're on a separate disk, not part of
> >>>> the postgres data directory)? Can/should I erase the WAL
> >>>> directory of the destination?
> >>>
> >>> Yes, you need the WAL files.
> >>
> >> Now I have two directly conflicting answers. You say the WAL
> >> files are needed even though the DB is shut off, and Payal Singh
> >> says I don't need the WAL files (but I don't think he cc'd the
> >> mailing list).
> >>
> >> Why are the WAL files necessary if the DB is shut off? Why
> >> can't they just be erased?
> >>
> >> It's a gigabyte of copying that I was hoping to avoid.
>
> > Payal is right. You don't need WAL for Cold backup.
>
> This experiment took far less time than reading the thread:
>
> kgrittn(at)Kevin-Desktop:~/pg/master$ pg_ctl -D Debug/data -m fast -w stop
> waiting for server to shut down.... done
> server stopped
> kgrittn(at)Kevin-Desktop:~/pg/master$ mkdir Debug/data/xlog2
> kgrittn(at)Kevin-Desktop:~/pg/master$ mv Debug/data/pg_xlog/*
> Debug/data/xlog2/
> kgrittn(at)Kevin-Desktop:~/pg/master$ rm -f Debug/data/logfile ; pg_ctl -D
> Debug/data -l Debug/data/logfile -w start || cat Debug/data/logfile
> waiting for server to start........ stopped waiting
> pg_ctl: could not start server
> Examine the log output.
> LOG: database system was shut down at 2013-12-06 15:31:27 CST
> LOG: creating missing WAL directory "pg_xlog/archive_status"
> LOG: invalid primary checkpoint record
> LOG: invalid secondary checkpoint record
> PANIC: could not locate a valid checkpoint record
> LOG: startup process (PID 15471) was terminated by signal 6: Aborted
> LOG: aborting startup due to startup process failure
>
> Now, if you're very clever you might be able to copy just
> *selected* WAL files. You've gotta ask yourself a question: "Do I
> feel lucky?" Well, do ya?
>
> --
> Kevin Grittner
> EDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>

--
Denish Patel,
OmniTi Computer Consulting Inc.
Database Architect,
http://omniti.com/does/data-management
http://www.pateldenish.com