[ADMIN] Problems rebuilding slave using pg_basebackup - Mailing list pgsql-admin

From Douglas Reed
Subject [ADMIN] Problems rebuilding slave using pg_basebackup
Date
Msg-id CAN7N4m3jAfnWV+1jq7-6S9wowEHU6Kdoomh3Rfe_RdSdt0sDfg@mail.gmail.com
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Responses Re: [ADMIN] Problems rebuilding slave using pg_basebackup
Re: [ADMIN] Problems rebuilding slave using pg_basebackup
List pgsql-admin

Hi

Sorry if this email was aready received but I sent it originally from my own email address
but received no response from the moderator so I assume that it may have got caught in the 
filter.

We are having a number of problems when we attempt to rebuild our  slave from its master

We have made about three attempts without success (using a proven set of notes)

It's been rebuilt several times over the last few months although the time between 
pg_basebackup being keyed and it actually copying data can be up to six minutes. 
And after completion the time taken from database startup to psql availability 
can also be several minutes while it processes any remaining logs.

Both machines are virtuals and are based with a leading cloud provider

OS Linux Centos6 (6.8 Final)

pg version 9.5.4

pg WAL settings on the master database

     max_wal_senders                = 5            
     max_wal_size                   = 4GB          
     min_wal_size                   = 256MB        
     wal_block_size                 = 8192         
     wal_buffers                    = 1MB          
     wal_compression                = off          
     wal_keep_segments              = 32           
     wal_level                      = hot_standby  
     wal_log_hints                  = off          
     wal_receiver_status_interval   = 10s          
     wal_receiver_timeout           = 1min         
     wal_retrieve_retry_interval    = 5s           
     wal_segment_size               = 16MB         
     wal_sender_timeout             = 1min         
     wal_sync_method                = fdatasync    
     wal_writer_delay               = 200ms        


Message from pg_basebackup

    [postgres@xxxxxxxxxx]$ pg_basebackup -h -IP_HIDDEN- -D /var/lib/pgsql/9.5/data -P -U postgres --xlog-method=stream
    pg_basebackup: could not receive data from WAL stream: server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
    269061959/269164935 kB (99%), 1/1 tablespace
    pg_basebackup: child process exited with error 1


Relevant error messages from master's log

    Nov  7 11:52:32 o8-data1 postgres[28558]: [6-1] user=[unknown],db=[unknown],app=[unknown]client=-IP_HIDDEN- LOG:  connection received: host=-IP_HIDDEN- port=41498
    Nov  7 11:52:32 o8-data1 postgres[28558]: [7-1] user=postgres,db=[unknown],app=[unknown]client=-IP_HIDDEN- LOG:  replication connection authorized: user=postgres
    Nov  7 13:51:44 o8-data1 postgres[28558]: [8-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- LOG:  could not send data to client: Broken pipe
    Nov  7 13:51:44 o8-data1 postgres[28558]: [9-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- ERROR:  base backup could not send data, aborting backup
    Nov  7 13:51:44 o8-data1 postgres[28558]: [10-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- FATAL:  connection to client lost
    Nov  7 13:51:44 o8-data1 postgres[28558]: [11-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- LOG:  disconnection: session time: 1:59:11.943 user=postgres database= host=-IP_HIDDEN- port=41498

    Nov  7 13:54:48 o8-data1 postgres[35445]: [6-1] user=[unknown],db=[unknown],app=[unknown]client=-IP_HIDDEN- LOG:  connection received: host=-IP_HIDDEN- port=44040
    Nov  7 13:54:48 o8-data1 postgres[35445]: [7-1] user=postgres,db=[unknown],app=[unknown]client=-IP_HIDDEN- LOG:  replication connection authorized: user=postgres
    Nov  7 15:09:20 o8-data1 postgres[35445]: [8-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- LOG:  could not send data to client: Broken pipe
    Nov  7 15:09:20 o8-data1 postgres[35445]: [9-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- ERROR:  base backup could not send data, aborting backup
    Nov  7 15:09:20 o8-data1 postgres[35445]: [10-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- FATAL:  connection to client lost
    Nov  7 15:09:20 o8-data1 postgres[35445]: [11-1] user=postgres,db=[unknown],app=pg_basebackupclient=-IP_HIDDEN- LOG:  disconnection: session time: 1:14:31.925 user=postgres database= host=-IP_HIDDEN- port=44040

Many thanks in advance



--
Douglas Reed
DBA
FSB Technology


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