Обсуждение: Taking rsynced base-backup without wal-archiving enabled
Hi all, Can I do a consistent file-system-level backup using the following procedure: 1) SELECT pg_start_backup(...) 2) rsync postgres data dir to another server 3) SELECT pg_stop_backup() 4) rsync pg_xlog directory From what I understand this should be similar to running pg_basebackup using the -x parameter, correct? One caveat seems to be that wal_keep_segments should be set "high enough". Can anybody tell what "high enough" usually is? Thanks in advance for you help! Best regards, Juergen
It depends on the database transactional activity,
observe how many new wal files are generated during a period equivalent to what it takes to do your base backup. I would set it to twice that number. Take into account that a checkpoint is issued at the beginning of the process. If you're lazy just try setting it to something very high such as 256 or more to prevent wal files being recycled during the process.
observe how many new wal files are generated during a period equivalent to what it takes to do your base backup. I would set it to twice that number. Take into account that a checkpoint is issued at the beginning of the process. If you're lazy just try setting it to something very high such as 256 or more to prevent wal files being recycled during the process.
2014-06-23 2:12 GMT-05:00 Jürgen Fuchsberger <juergen.fuchsberger@gmx.at>:
Hi all,
Can I do a consistent file-system-level backup using the following
procedure:
1) SELECT pg_start_backup(...)
2) rsync postgres data dir to another server
3) SELECT pg_stop_backup()
4) rsync pg_xlog directory
From what I understand this should be similar to running pg_basebackup
using the -x parameter, correct? One caveat seems to be that
wal_keep_segments should be set "high enough". Can anybody tell what
"high enough" usually is?
Thanks in advance for you help!
Best regards,
Juergen
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On Mon, Jun 23, 2014 at 09:28:06PM -0500, Rene Romero Benavides wrote: > It depends on the database transactional activity, > observe how many new wal files are generated during a period equivalent to what > it takes to do your base backup. I would set it to twice that number. Take into > account that a checkpoint is issued at the beginning of the process. If you're > lazy just try setting it to something very high such as 256 or more to prevent > wal files being recycled during the process. > > > 2014-06-23 2:12 GMT-05:00 J rgen Fuchsberger <juergen.fuchsberger@gmx.at>: > > Hi all, > > Can I do a consistent file-system-level backup using the following > procedure: > > 1) SELECT pg_start_backup(...) > 2) rsync postgres data dir to another server > 3) SELECT pg_stop_backup() > 4) rsync pg_xlog directory > > >From what I understand this should be similar to running pg_basebackup > using the -x parameter, correct? One caveat seems to be that > wal_keep_segments should be set "high enough". Can anybody tell what > "high enough" usually is? I am coming late to this thread, but it seems easier for the user to set archive_command to something meaningful during start/stop backup, and set it to /bin/true at other times. I realize they can't turn archive_mode on/off without a restart. -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. +
i think you could try pg_basebackup tools. it has options to achieve same thing as you wanted. but need pgdata on destination emptied. if you really need to do the exact thing as you stated, then you need to set postgres to keep high enough number of xlog files on master to ensure that needed xlog files not removed prior to completed backup. but no guarantee, since the database activity is not a static one.
On Mon, Aug 4, 2014 at 11:15 PM, Bruce Momjian <bruce@momjian.us> wrote:
On Mon, Jun 23, 2014 at 09:28:06PM -0500, Rene Romero Benavides wrote:
> It depends on the database transactional activity,
> observe how many new wal files are generated during a period equivalent to what
> it takes to do your base backup. I would set it to twice that number. Take into
> account that a checkpoint is issued at the beginning of the process. If you're
> lazy just try setting it to something very high such as 256 or more to prevent
> wal files being recycled during the process.
>
>
> 2014-06-23 2:12 GMT-05:00 J rgen Fuchsberger <juergen.fuchsberger@gmx.at>:
>
> Hi all,
>
> Can I do a consistent file-system-level backup using the following
> procedure:
>
> 1) SELECT pg_start_backup(...)
> 2) rsync postgres data dir to another server
> 3) SELECT pg_stop_backup()
> 4) rsync pg_xlog directory
>
> >From what I understand this should be similar to running pg_basebackup
> using the -x parameter, correct? One caveat seems to be that
> wal_keep_segments should be set "high enough". Can anybody tell what
> "high enough" usually is?
I am coming late to this thread, but it seems easier for the user to set
archive_command to something meaningful during start/stop backup, and
set it to /bin/true at other times. I realize they can't turn
archive_mode on/off without a restart.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
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