DRBD故障處理
drbd1主,drbd2輔
1，正常情況下狀態：
[root@drbd1 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r----
ns:2144476 nr:0 dw:36468 dr:2115769 al:14 bm:129 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
[root@drbd2 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:Connected ro:Secondary/Primary ds:UpToDate/UpToDate C r----
ns:0 nr:2141684 dw:2141684 dr:0 al:0 bm:130 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
2，drbd1故障後
drbd1狀態：
[root@drbd1 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:StandAlone ro:Primary/Unknown ds:UpToDate/DUnknown r----
ns:4 nr:102664 dw:102668 dr:157 al:1 bm:8 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
drbd2的狀態：
[root@drbd2 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:WFConnection ro:Secondary/Unknown ds:UpToDate/DUnknown C r----
ns:0 nr:2141684 dw:2141684 dr:0 al:0 bm:130 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
3，處理方法：
a，將secondary配置成primary角色
[root@drbd2 ~]# drbdsetup /dev/drbd0 primary -o
[root@drbd2 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:WFConnection ro:Primary/Unknown ds:UpToDate/Outdated C r----
ns:0 nr:2141684 dw:2141684 dr:0 al:0 bm:130 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
掛載：
[root@drbd2 /]# mount /dev/drbd0 /data1
[root@drbd2 data1]# ll
total 10272
-rw-r--r-- 1 root root 10485760 Feb 13 11:26 aa.img
drwx------ 2 root root 16384 Feb 13 11:25 lost+found
這個時候drbd2開始提供服務，開始寫數據
drbd1主恢復正常後：
[root@drbd1 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:StandAlone ro:Primary/Unknown ds:UpToDate/DUnknown r----
ns:2144476 nr:0 dw:36484 dr:2115769 al:14 bm:129 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:8
drbd1狀態是:StandAlone，此時，drbd1是不會和drbd2互相聯系的
我們來查看下日志：
[root@drbd1 ~]# tailf /var/log/messages
Feb 13 16:14:27 drbd1 kernel: block drbd0: helper command: /sbin/drbdadm split-brain minor-0
Feb 13 16:14:27 drbd1 kernel: block drbd0: helper command: /sbin/drbdadm split-brain minor-0 exit code 0 (0x0)
Feb 13 16:14:27 drbd1 kernel: block drbd0: conn( WFReportParams -> Disconnecting )
Feb 13 16:14:27 drbd1 kernel: block drbd0: error receiving ReportState, l: 4!
Feb 13 16:14:27 drbd1 kernel: block drbd0: asender terminated
Feb 13 16:14:27 drbd1 kernel: block drbd0: Terminating drbd0_asender
Feb 13 16:14:27 drbd1 kernel: block drbd0: Connection closed
Feb 13 16:14:27 drbd1 kernel: block drbd0: conn( Disconnecting -> StandAlone )
Feb 13 16:14:27 drbd1 kernel: block drbd0: receiver terminated
Feb 13 16:14:27 drbd1 kernel: block drbd0: Terminating drbd0_receiver
腦裂出現！
解決方法：
1>,我們需要將現在的drbd1角色修改為secondary
[root@drbd1 ~]# drbdadm secondary r0
[root@drbd1 ~]# drbdadm -- --discard-my-data connect r0 ##該命令告訴drbd，secondary上的數據不正確，以primary上的數據為准。
2>，我們還需要在drbd2上執行下面操作
[root@drbd2 /]# drbdadm connect r0
這樣drbd1就能和drbd2開始連接上了，並且保證數據不會丟失：
[root@drbd1 ~]# cat /proc/drbd
version: 8.3.8 (api:88/proto:86-94)
srcversion: 299AFE04D7AFD98B3CA0AF9
0: cs:Connected ro:Secondary/Primary ds:UpToDate/UpToDate C r----
ns:0 nr:20592 dw:20592 dr:0 al:0 bm:4 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
