Re: replication timeout in pg_basebackup - Mailing list pgsql-general

From Haribabu Kommi
Subject Re: replication timeout in pg_basebackup
Date
Msg-id CAJrrPGcFfjqBMSLrKvze7D-dA+3kMciFpRzYxa4_Cs9PB+hifg@mail.gmail.com
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In response to replication timeout in pg_basebackup  ("Aggarwal, Ajay" <aaggarwal@verizon.com>)
Responses Re: replication timeout in pg_basebackup  ("Aggarwal, Ajay" <aaggarwal@verizon.com>)
List pgsql-general
On Mon, Mar 10, 2014 at 12:52 PM, Aggarwal, Ajay <aaggarwal@verizon.com> wrote:
Our environment: Postgres version 9.2.2 running on CentOS 6.4

Our backups using pg_basebackup are frequently failing with following error
"pg_basebackup: could not send feedback packet: server closed the connection unexpectedly       This probably means the server terminated abnormally       before or while processing the request."

We are invoking pg_basebackup with these arguments : pg_basebackup -D backup_dir -X stream -l backup_dir
In postgres logs we see this log message "terminating walsender process due to replication timeout".

Our replication timeout is default 60 seconds. If we increase the replication time to say 180 seconds, we see better results but backups still fail occasionally.

Running strace on pg_basebackup process, we see that the fsync() call takes significant time and could be responsible for causing this timeout in postgres.

Use the pg_test_fsync utility which is available in postgresql contrib module to test your system sync methods performance. 
 
Has anybody else run into the same issue? Is there a way to run pg_basebackup without fsync() ?

As of now there is no such options available, I feel it is better to find why the sync is taking time?
 
Regards,
Hari Babu
Fujitsu Australia

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