Xtrabackup流備與恢復
Xtrabackup是MySQL資料庫的備份不可多得的工具之一。提供了全備，增備，資料庫級別，表級別備份等等。最牛X的還有不落盤的備份，即流備份方式。對於伺服器上空間不足，或是搭建主從，直接使用流式備份大大簡化了備份後的壓縮複製所帶來的更多開銷。Xtrabackup支援tar格式以及xbstream格式的流備份。本文即是對此展開的相關描述。
1、基於tar格式備份
a、備份到本地
# innobackupex --stream=tar /tmp >/backup/bak.tar ###非壓縮方式
# innobackupex --stream=tar /tmp |gzip >/backup/bakz.tar.gz ###壓縮方式
# ls -hltr
total 42M
-rw-r--r-- 1 root root 39M Apr 15 17:23 bak.tar
-rw-r--r-- 1 root root 3.3M Apr 15 17:24 bakz.tar.gz
###解壓備份
# mkdir bak bakz
# tar -xivf bak.tar -C /backup/bak
# tar -xizvf bakz.tar.gz -C /backup/bakz
# du -sh *
38M bak
39M bak.tar
38M bakz
3.3M bakz.tar.gz
b、備份到遠端
# innobackupex --stream=tar /tmp | ssh [email protected] \ "cat - > /backup/bak.tar" ###非壓縮方式
# innobackupex --stream=tar /tmp | ssh
2、使用xbstream格式備份
a、備份到本地
# innobackupex --stream=xbstream /tmp >/backup/bak.xbstream ###非壓縮方式
# innobackupex --stream=xbstream --compress /tmp >/backup/bak_compress.xbstream ###壓縮方式
# ls -hltr
total 43M
-rw-r--r-- 1 root root 37M Apr 15 17:41 bak.xbstream
-rw-r--r-- 1 root root 6.0M Apr 15 17:41 bak_compress.xbstream
###解壓備份
# mkdir bk bk_compress
# xbstream -x < bak.xbstream -C /backup/bk ###解壓xbstream格式
###解壓xbstream格式，compress引數的備份
# xbstream -x < bak_compress.xbstream -C /backup/bk_compress ###首先解壓xbstream
# for bf in `find . -iname "*\.qp"`; do qpress -d $bf $(dirname $bf) && rm $bf; done ###再解壓qp壓縮格式
# innobackupex --decompress /backup/bk_compress ###如果xtrabackup版本大於2.1.4，可以直接通過該方式解壓
b、備份到遠端
###使用壓縮備份到遠端並解壓
# innobackupex --stream=xbstream --compress /tmp | ssh [email protected] "xbstream -x -C /backup/stream"
3、流備份的全備與增備
###全備資料庫，使用--extra-lsndir引數生產checkpoints檔案
# innobackupex --stream=xbstream --compress --extra-lsndir=/backup/chkpoint /tmp >/backup/bak_compress.xbstream
# more /backup/chkpoint/xtrabackup_checkpoints
backup_type = full-backuped
from_lsn = 0
to_lsn = 8408290
last_lsn = 8408290
compact = 0
### Author : Leshami
### Blog : http://blog.csdn.net/leshami
###增備資料庫，如果後續還需要再次增備，則可以再次指定--extra-lsndir，如果與上次備份指定相同的位置，該檔案被覆蓋
# innobackupex --compress --incremental --extra-lsndir=/backup/chkpoint --incremental-basedir=/backup/chkpoint \
> --stream=xbstream /tmp >/backup/bak_compress_inc.xbstream
4、流備份的異機恢復
###備份到異機
# innobackupex --stream=xbstream --extra-lsndir=/backup/chkpoint /tmp | [email protected] "xbstream -x -C /backup/stream"
# innobackupex --incremental --extra-lsndir=/backup/chkpoint --incremental-basedir=/backup/chkpoint --stream=xbstream \
> /tmp | ssh [email protected] "xbstream -x -C /backup/stream_inc"
###異機恢復，copy-back及後續步驟省略
# innobackupex --apply-log --redo-only /backup/stream
# innobackupex --apply-log /backup/stream --incremental-dir=/backup/stream_inc
5、其它注意事項
a、如果使用xbstream格式異機備份時，異機未安裝xbstream(封裝在xtrabackup中)則出現如下錯誤提示。
bash: xbstream: command not found
xtrabackup: Error writing file 'UNOPENED' (Errcode: 32 - Broken pipe)
xb_stream_write_data() failed.
compress: write to the destination stream failed.
xtrabackup: Error writing file 'UNOPENED' (Errcode: 32 - Broken pipe)
xb_stream_write_data() failed.
xtrabackup: Error writing file 'UNOPENED' (Errcode: 32 - Broken pipe)
[01] xtrabackup: Error: xtrabackup_copy_datafile() failed.
[01] xtrabackup: Error: failed to copy datafile.
innobackupex: Error: The xtrabackup child process has died at /usr/bin/innobackupex line 2681.
b、異機備份時需要建立等效性，如下示例
# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
29:45:ee:8d:b3:55:f1:5f:2f:da:2a:88:0c:0d:37:9f [email protected]
###copy 公鑰到遠端主機
# ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]
21
The authenticity of host '192.168.1.7 (192.168.1.7)' can't be established.
RSA key fingerprint is 1d:7c:40:98:ef:de:6f:b8:8c:b2:87:72:0e:79:db:0a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.7' (RSA) to the list of known hosts.
[email protected]'s password:
Now try logging into the machine, with "ssh '[email protected]'", and check in:
.ssh/authorized_keys
to make sure we haven't added extra keys that you weren't expecting.
###驗證等效性是否成功
# ssh 192.168.1.7 date;
Wed Apr 15 17:55:31 CST 2015
c、使用tar格式遠端增量備份時收到如下提示，即只支援xbstream
xtrabackup: error: streaming incremental backups are incompatible with the
'tar' streaming format. Use --stream=xbstream instead.
d、用流備份，預設的臨時目錄都是系統的/tmp目錄，需要保證該目錄有足夠的空間，或指定--tmpdir選項
e、流備份日誌輸出
innobackupex --stream=xbstream /tmp 2>>"$backupLog" | gzip > "$backup_file" 2>>"$backupLog"