Re: Starting new cluster from base backup

[Guillaume Drolet <droletguillaume@xxxxxxxxx>]

This provides part of the answer to my previous post, from the 9.4 doc (although I'm running 9.3 but I guess the second phrase in the paragraph applies to my case):

Tablespaces will in plain format by default be backed up to the same path they have on the server, unless the option --tablespace-mapping is used. Without this option, running a plain format base backup on the same host as the server will not work if tablespaces are in use, because the backup would have to be written to the same directory locations as the original tablespaces.

I know the -T option is not available in 9.3. Is there another way to circumvent the problem and still be able to backup using -X stream and plain format when tablespace have been created elsewhere?

Thanks!

2015-02-17 9:54 GMT-05:00 Guillaume Drolet <droletguillaume@xxxxxxxxx>:

Adrian: thanks for this information.

I tried running pg_basebackup in plain format with option -X stream (pg_basebackup -D "F:\208376PT\db" -X stream -l "208376PT17022015" -U postgres -P) but I got the message:

pg_basebackup: directory "E:\Data\Database" exists but is not empty"

I creatde a tablespace using CREATE TABLESPACE at the location mentioned in the message. According to what I read online about this, this message is issued when a tablespace was created under PGDATA. In my case, only the directory junction pointing to my tablespace (on a different drive than PGDATA) exists under PGDATA, not the tablespace itself.

The only way I can run pg_basebackup with WAL files is with option -Ft and -X fetch. I'd much prefer using plain mode since my 670 GB tablespace takes a lot of time to extract when tarred. Is there another way to approach this?

Thanks.

2015-02-16 15:21 GMT-05:00 Adrian Klaver <adrian.klaver@xxxxxxxxxxx>:

On 02/16/2015 11:31 AM, Guillaume Drolet wrote:

Dear listers,

I want to move a cluster from one machine to another. I used
pg_basebackup to create an archive and copied/extracted it over the old
PGDATA location on the new machine (the server was stopped). If I start
pgsql I get these messages in my log file:

2015-02-16 14:29:12 EST LOG:  database system was interrupted; last
known up at 2015-02-07 06:31:41 EST
2015-02-16 14:29:12 EST LOG:  invalid checkpoint record
2015-02-16 14:29:12 EST FATAL:  could not locate required checkpoint record
2015-02-16 14:29:12 EST HINT:  If you are not restoring from a backup,
try removing the file "E:/data/backup_label".
2015-02-16 14:29:12 EST LOG:  startup process (PID 3148) exited with
exit code 1
2015-02-16 14:29:12 EST LOG:  aborting startup due to startup process
failure

I assume this is due to the fact the pg_xlog folder is empty (this is
how pg_basebackup makes it in the archive) and that I haven't supplied a
recovery.conf file with the restore restore_command = 'copy
"E:\\archivedir\\%f" "%p"', and the archived WAL files.

Now my question is: it this a correct way of moving a cluster between
machines?

If yes, what WAL files will I put in pg_xlog? Would I have needed to
copy those that were in the old machine right after the base backup?

If this is not the right way to do it, what is the best way?

http://www.postgresql.org/docs/9.3/interactive/app-pgbasebackup.html

"
-X method
--xlog-method=method

    Includes the required transaction log files (WAL files) in the backup. This will include all transaction logs generated during the backup. If this option is specified, it is possible to start a postmaster directly in the extracted directory without the need to consult the log archive, thus making this a completely standalone backup ....
"

There is more under -X, so I would read the whole section.

Thanks a lot for your help,

Guillaume

--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx