不传输这些 WAL 文件的恢复命令有什么问题？
barman recover --target-time "2017-05-16 16:39:02.235780+00:00" \
--remote-ssh-command "ssh postgres@52.212.62.91" \
main-db latest /var/lib/postgresql/9.4/main
这是我的过程...
主数据库已关闭（模拟故障），但最近有一个备份，并且 WAL 文件已从 main-db 服务器传送。
barman@ip-172-30-2-77:~/main-db$ barman check main-db
Server main-db:
PostgreSQL: FAILED
directories: OK
retention policy settings: OK
backup maximum age: OK (interval provided: 1 day, latest backup age: 1 hour, 3 minutes, 46 seconds)
compression settings: OK
failed backups: OK (there are 0 failed backups)
minimum redundancy requirements: OK (have 1 backups, expected at least 0)
ssh: OK (PostgreSQL server)
not in recovery: OK
archiver errors: OK
在 Barman 服务器上，我们可以看到自上次
barman backup main-db运行以来归档了 6 个 WAL 文件。
barman@ip-172-30-2-77:~/main-db$ ls -lah
total 22M
drwxrwxr-x 2 barman barman 4.0K May 16 17:08 .
drwxrwxr-x 3 barman barman 4.0K May 16 17:08 ..
-rw------- 1 barman barman 28K May 16 16:39 0000000100000001000000E2
-rw------- 1 barman barman 204 May 16 16:39 0000000100000001000000E2.00000090.backup
-rw------- 1 barman barman 84K May 16 16:44 0000000100000001000000E3
-rw------- 1 barman barman 37K May 16 16:49 0000000100000001000000E4
-rw------- 1 barman barman 30K May 16 16:54 0000000100000001000000E5
-rw------- 1 barman barman 8.9M May 16 16:58 0000000100000001000000E6
-rw------- 1 barman barman 9.1M May 16 16:59 0000000100000001000000E7
-rw------- 1 barman barman 2.6M May 16 17:04 0000000100000001000000E8
-rw------- 1 barman barman 543K May 16 17:07 0000000100000001000000E9
现在我将运行recover命令，使用最新的备份+WAL文件来恢复备用数据库服务器，如下：
barman@ip-172-30-2-77:~/main-db$ barman list-server
main-db - Main DB Server
standby-db - Standby DB Server
barman@ip-172-30-2-77:~/main-db$ barman list-backup main-db
main-db 20170516T163617 - Tue May 16 16:39:02 2017 - Size: 4.0 GiB - WAL Size: 21.1 MiB
barman@ip-172-30-2-77:~/main-db$ barman show-backup main-db 20170516T163617
Backup 20170516T163617:
Server Name : main-db
Status : DONE
PostgreSQL Version : 90411
PGDATA directory : /var/lib/postgresql/9.4/main
Base backup information:
Disk usage : 4.0 GiB (4.0 GiB with WALs)
Incremental size : 4.0 GiB (-0.00%)
Timeline : 1
Begin WAL : 0000000100000001000000E2
End WAL : 0000000100000001000000E2
WAL number : 1
WAL compression ratio: 99.83%
Begin time : 2017-05-16 16:36:17.369993+00:00
End time : 2017-05-16 16:39:02.235780+00:00
Begin Offset : 144
End Offset : 4912
Begin XLOG : 1/E2000090
End XLOG : 1/E2001330
WAL information:
No of files : 7
Disk usage : 21.1 MiB
WAL rate : 16.91/hour
Compression ratio : 81.21%
Last available : 0000000100000001000000E9
Catalog information:
Retention Policy : VALID
Previous Backup : - (this is the oldest base backup)
Next Backup : - (this is the latest base backup)
barman@ip-172-30-2-77:~/main-db$ barman recover --target-time "2017-05-16 16:39:02.235780+00:00" \
--remote-ssh-command "ssh postgres@52.212.62.91" \
main-db latest /var/lib/postgresql/9.4/main
Starting remote restore for server main-db using backup 20170516T163617
Destination directory: /var/lib/postgresql/9.4/main/
Doing PITR. Recovery target time: '2017-05-16 16:39:02.235780+00:00'
Copying the base backup.
Copying required WAL segments.
Generating recovery.conf
Your PostgreSQL server has been successfully prepared for recovery!
现在关注备用数据库服务器上的 Postgresql 数据目录（/var/lib/postgresql/9.4/main）。
postgres@ip-172-30-0-66:~/9.4/main$ pwd
/var/lib/postgresql/9.4/main
postgres@ip-172-30-0-66:~/9.4/main$ ls
backup_label pg_hba.conf pg_replslot pg_tblspc postgresql.conf
barman_xlog pg_ident.conf pg_serial pg_twophase postgresql.conf.origin
base pg_log pg_snapshots PG_VERSION recovery.conf
global pg_logical pg_stat pg_xlog
pg_clog pg_multixact pg_stat_tmp postgresql.auto.conf
pg_dynshmem pg_notify pg_subtrans postgresql.auto.conf.origin
postgres@ip-172-30-0-66:~/9.4/main$ ls barman_xlog/
0000000100000001000000E2 0000000100000001000000E2.00000090.backup
我们可以看到以下 WAL 文件都没有使用恢复命令传输。
- 0000000100000001000000E3
- 0000000100000001000000E4
- 0000000100000001000000E5
- 0000000100000001000000E6
- 0000000100000001000000E7
- 0000000100000001000000E8
- 0000000100000001000000E9
但是，我可以使用 barman-cli 的barman-restore-wal命令来拉动它们。所以这告诉我他们在酒保服务器上是明确可用的。这是我用来恢复 WAL 文件的 recovery.conf 文件。
root@ip-172-30-0-66:/var/lib/postgresql/9.4/maincat recovery.conf
The 'barman-wal-restore' command is provided in the 'barman-cli' package
standby_mode = 'on'
trigger_file = '/var/lib/postgresql/9.4/trigger'
restore_command = 'barman-wal-restore 52.51.36.41 main-db %f %p'
现在我们可以看到所有的 WAL 文件都是从酒保服务器中提取的。
root@ip-172-30-0-66:/var/lib/postgresql/9.4/mainls -lah pg_xlog/
total 129M
drwx------ 3 postgres postgres 4.0K May 16 17:59 .
drwx------ 19 postgres postgres 4.0K May 16 17:58 ..
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E2
-rw-rw-r-- 1 postgres postgres 324 May 16 17:54 0000000100000001000000E2.00000090.backup
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E3
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E4
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E5
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E6
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E7
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E8
-rw------- 1 postgres postgres 16M May 16 17:56 0000000100000001000000E9
drwxrwxr-x 2 postgres postgres 4.0K May 16 17:56 archive_status
-rw------- 1 postgres postgres 0 May 16 17:59 RECOVERYXLOG