Re: WAL shipping question

> This basically archives the data in the primary server
itself...right!!!
> But how can I set up continuous archiving from primary to a directory

> (WAL archive directory) on the stand-by server ?

The closest thing to a worked out example of how to do this I'm aware
of
is at http://archives.postgresql.org/sydpug/2006-10/msg00001.php

That uses rsync as the transport mechanism for reasons it explains (the

'atomic copy' feature). You can certainly replicate that using ssh,
but
you may have to use a secondary directory to hold files while they're
being transferred so the stand-by doesn't try to do something with the
partial copies. Mounting filesystems and copying the files over
Samba/NFS/etc. is another approach with its own issues. It's been my
experience that remote filesystems will hang in odd ways when there's a

connectivity problem, while copying with ssh/scp gives you a more
predictable copied/failed return code without retrying too hard.
PostgreSQL can tolerate the archive_command spitting back an error just

fine and will retry automatically, I prefer not to expose the server to
a
situation where the archive_command might not return quickly.

The main thing that's improved in 8.3 is the integration of pg_standby
as
a more rugged restore_command than most people were coding on their
own:

http://www.postgresql.org/docs/8.3/static/pgstandby.html

You should use it instead of the example restore.sh included in the
message I referenced above.

Thanks for your reply. I will look into the pg_standby and rsync.

I currently have this in my config file

archive_command = 'cp -i "%p" /export/home/user/archivedir/"%f" &&
scp -i userKey "%p" user(at)172(dot)31(dot)0(dot)27:/export/home/user/archivedir/"%f"'

userKey is a public-private key generated without the passphrase. This works...
scp -i userKey dummy user(at)172(dot)31(dot)0(dot)27:/export/home/user/archivedir
and it just copies the dummy file from primary to standby without prompting for a password.

It doesnt scp the wal files from primary to stand-by when i add it to archive_command as given above. I get this error
Warning: Identity file userKey does not exist.
ssh_askpass: exec(/usr/lib/ssh/ssh-askpass): No such file or directory
Write failed: Broken pipe
lost connection
LOG: archive command "cp -i "pg_xlog/000000010000000000000039" /export/home/user/archivedir/"000000010000000000000039" && scp -i userKey "pg_xlog/000000010000000000000039" user(at)172(dot)31(dot)0(dot)27:/export/home/user/archivedir/"000000010000000000000039"" failed: return code 256

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