Re: File removed while backup is running

Hi,

that is generally not a problem. _fsm  is the "Free Space Map" file (http://www.postgresql.org/docs/9.4/static/storage-fsm.html). It's OK and normal, that files change or even disappear within PGDATA directory during backup - because the Postgres cluster is still operational. Those changes end up in the WAL files and that is why you need those from the start of the backup. This is also described in the manual:

"Some file system backup tools emit warnings or errors if the files they are trying to copy change while the copy proceeds. When taking a base backup of an active database, this situation is normal and not an error. However, you need to ensure that you can distinguish complaints of this sort from real errors. For example, some versions of rsync return a separate exit code for "vanished source files", and you can write a driver script to accept this exit code as a non-error case. Also, some versions of GNU tar return an error code indistinguishable from a fatal error if a file was truncated while tar was copying it. Fortunately, GNU tar versions 1.16 and later exit with 1 if a file was changed during the backup, and 2 for other errors. With GNU tar version 1.23 and later, you can use the warning options --warning=no-file-changed --warning=no-file-removed to hide the related warning messages."

http://www.postgresql.org/docs/9.4/interactive/continuous-archiving.html#BACKUP-LOWLEVEL-BASE-BACKUP


hth

Jan

Am 2015-05-21 09:04, schrieb Mario Aguado:

Hi,

I have two postgres cluster in 9.4 version and all run backups
correctly. Recently I add a new cluster and the backup doesnt work on
it. 

All databases have archive_mode = on and wal_level=archive

My backup has this steeps:
 
SELECT pg_start_backup(${clustername});"
tar PGDATA and TABLESPACES
Select pg_stop_backup();
tar WAL files

With this database when I run backup I get errors like:

t3_28961_fsm: File removed before we read it

I dont know what file type is t3_28961_fsm.

If I go to tablespace dir i have several t files and this file types
are adding and removing continously.

-rw------- 1 postgres postgres 8.0K May 21 09:01 t3_29094
-rw------- 1 postgres postgres    0 May 21 09:01 t3_29087
-rw------- 1 postgres postgres 8.0K May 21 09:01 t3_29093

Im looking for this error but i didnt found any.

Any idea?

Thanks in advance.

Regards.

Mario

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