Centos5.5文件实时同步(DRBD)的实现
Distributed Replicated Block Device(DRBD)是一个用软件实现的、无共享的、服务器之间镜像块设备内容的存储复制解决方案。数据镜像：实时、透明、同步，异步。DRBD的核心功能通过Linux的内核实现。下面我用Centos5.5系统搭建服务，希望能对大家有帮助。
复制模式：3种模式：
协议A：异步复制协议。本地写成功后立即返回，数据放在发送buffer中，可能丢失。
协议B：内存同步（半同步）复制协议。本地写成功并将数据发送到对方后立即返回，如果双机掉电，数据可能丢失。
协议C：同步复制协议。本地和对方写成功确认后返回。如果双机掉电或磁盘同时损坏，则数据可能丢失。
1.配置两台服务器的网络参数
服务器A:
[root@centos ~]# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:C0:BB:83 inet addr:2.2.2.135 Bcast:2.2.2.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:fec0:bb83/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:46877 errors:0 dropped:0 overruns:0 frame:0 TX packets:2334 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3481575 (3.3 MiB) TX bytes:259845 (253.7 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1065 errors:0 dropped:0 overruns:0 frame:0 TX packets:1065 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1957592 (1.8 MiB) TX bytes:1957592 (1.8 MiB) [root@centos ~]# hostname centos [root@centos ~]# vim /etc/hosts 2.2.2.135 centos --添加以下两行 2.2.2.145 centos1
服务器B:
[root@centos1 ~]# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:EC:53:12 inet addr:2.2.2.145 Bcast:2.2.2.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:feec:5312/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:3894 errors:0 dropped:0 overruns:0 frame:0 TX packets:108 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:292745 (285.8 KiB) TX bytes:11858 (11.5 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1470 errors:0 dropped:0 overruns:0 frame:0 TX packets:1470 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:3399758 (3.2 MiB) TX bytes:3399758 (3.2 MiB) [root@centos1 ~]# hostname centos1 [root@centos1 ~]# vim /etc/hosts 2.2.2.135 centos --添加以下两行 2.2.2.145 centos1 [root@centos1 ~]# ping 2.2.2.135 -c 2 PING 2.2.2.135 (2.2.2.135) 56(84) bytes of data. 64 bytes from 2.2.2.135: icmp_seq=1 ttl=64 time=3.61 ms 64 bytes from 2.2.2.135: icmp_seq=2 ttl=64 time=3.05 ms --- 2.2.2.135 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1000ms rtt min/avg/max/mdev = 3.054/3.332/3.611/0.284 ms [root@centos1 ~]#
2.磁盘分区(两台服务器分相同大小 的分区)
[root@centos ~]# fdisk /dev/sdb --在两台服务器分别添加一个同步分区 Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 1 First cylinder (1-64, default 1): Using default value 1 Last cylinder or +size or +sizeM or +sizeK (1-64, default 64): +500M Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks. [root@centos ~]# partx -a /dev/sdb BLKPG: Device or resource busy error adding partition 1 [root@centos ~]#
2.下载安装DRBD软件
服务器A:
[root@centos /]# wget http://vault.centos.org/5.5/extras/i386/RPMS/drbd83-8.3.8-1.el5.centos.i386.rpm
[root@centos /]# wget http://vault.centos.org/5.5/extras/i386/RPMS/kmod-drbd83-8.3.8-1.el5.centos.i686.rpm
[root@centos1 /]# rpm -ivh drbd83-8.3.8-1.el5.centos.i386.rpm
Preparing... ########################################### [100%]
1:drbd83 ########################################### [100%]
[root@centos1 /]# rpm -ivh kmod-drbd83-8.3.8-1.el5.centos.i686.rpm
Preparing... ########################################### [100%]
1:kmod-drbd83 ########################################### [100%]
[root@centos ~]# vim /etc/drbd.conf
:r /usr/share/doc/drbd83-8.3.8/drbd.conf --导入配置文件
:wq --保存
[root@centos ~]# vim /etc/drbd.d/web.res --添加如下代码
resource web{
on centos {
device /dev/drbd0;
disk /dev/sdb1;
address 2.2.2.135:7781;
meta-disk internal;
}
on centos1 {
device /dev/drbd0;
disk /dev/sdb1;
address 2.2.2.145:7781;
meta-disk internal;
}
}
服务器B:
[root@centos1 /]# rpm -ivh drbd83-8.3.8-1.el5.centos.i386.rpm
Preparing... ########################################### [100%]
1:drbd83 ########################################### [100%]
[root@centos1 /]# rpm -ivh kmod-drbd83-8.3.8-1.el5.centos.i686.rpm
Preparing... ########################################### [100%]
1:kmod-drbd83 ########################################### [100%]
[root@centos ~]# vim /etc/drbd.conf
:r /usr/share/doc/drbd83-8.3.8/drbd.conf --导入配置文件
:wq --保存
[root@centos ~]# vim /etc/drbd.d/web.res --添加如下代码
resource web{
on centos {
device /dev/drbd0;
disk /dev/sdb1;
address 2.2.2.135:7781;
meta-disk internal;
}
on centos1 {
device /dev/drbd0;
disk /dev/sdb1;
address 2.2.2.145:7781;
meta-disk internal;
}
}
3.初始配置和启动服务
服务器A:
[root@centos ~]# drbdadm create-md web ..................... .................... New drbd meta data block successfully created. --有这个结尾表示成功
服务器B:
[root@centos1 ~]# drbdadm create-md web ..................... .................... New drbd meta data block successfully created. --有这个结尾表示成功
服务器A:
[root@centos ~]# /etc/init.d/drbd start --启动服务 Starting DRBD resources: [ web Found valid meta data in the expected location, 509927424 bytes into /dev/sdb1. d(web) n(web) ]. [root@centos ~]#
服务器B:
[root@centos1 ~]# /etc/init.d/drbd start Starting DRBD resources: [ web Found valid meta data in the expected location, 509927424 bytes into /dev/sdb1. d(web) n(web) ].......... *************************************************************** DRBD's startup script waits for the peer node(s) to appear. - In case this node was already a degraded cluster before the reboot the timeout is 0 seconds. [degr-wfc-timeout] - If the peer was available before the reboot the timeout will expire after 0 seconds. [wfc-timeout] (These values are for resource 'web'; 0 sec -> wait forever) To abort waiting enter 'yes' [ 10]: . [root@centos1 ~]#
查看drbd的状态
[root@centos ~]# cat /proc/drbd version: 8.3.8 (api:88/proto:86-94) GIT-hash: d78846e52224fd00562f7c225bcc25b2d422321d build by [email protected], 2010-06-04 08:04:16 0: cs:Connected ro:Secondary/Secondary ds:Inconsistent/Inconsistent C r---- ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:497928 [root@centos ~]#
4.设置服务器A为主设备
[root@centos ~]# drbdadm -- --overwrite-data-of-peer primary web --设主设备 [root@centos ~]# cat /proc/drbd --查看同步信息 version: 8.3.8 (api:88/proto:86-94) GIT-hash: d78846e52224fd00562f7c225bcc25b2d422321d build by [email protected], 2010-06-04 08:04:16 0: cs:SyncSource ro:Primary/Secondary ds:UpToDate/Inconsistent C r---- ns:2208 nr:0 dw:0 dr:2208 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:495720 [>....................] sync'ed: 0.9% (495720/497928)K delay_probe: 6685 finish: 0:20:39 speed: 368 (368) K/sec [root@centos ~]#...................... --等一下看是否同步完毕 [root@centos ~]# cat /proc/drbd --同步完成了 version: 8.3.8 (api:88/proto:86-94) GIT-hash: d78846e52224fd00562f7c225bcc25b2d422321d build by [email protected], 2010-06-04 08:04:16 0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r---- ns:497928 nr:0 dw:0 dr:497928 al:0 bm:31 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0 [root@centos ~]# mkfs.ext3 /dev/drbd0 --格式化设备 mke2fs 1.39 (29-May-2006) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) 124928 inodes, 497928 blocks 24896 blocks (5.00%) reserved for the super user First data block=1 Maximum filesystem blocks=67633152 61 block groups 8192 blocks per group, 8192 fragments per group 2048 inodes per group Superblock backups stored on blocks: 8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409 Writing inode tables: done Creating journal (8192 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 32 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. [root@centos ~]# mount /dev/drbd0 /mnt/ [root@centos ~]# df -TH Filesystem Type Size Used Avail Use% Mounted on /dev/sda2 ext3 11G 3.6G 6.2G 37% / /dev/sda1 ext3 510M 17M 467M 4% /boot tmpfs tmpfs 264M 0 264M 0% /dev/shm /dev/drbd0 ext3 494M 11M 458M 3% /mnt [root@centos ~]#
5.测试主从切换功能
服务器A:
[root@centos ~]# cp -a /etc/passwd /etc/shadow /mnt/ --在主设备考备文件 [root@centos ~]# ll /mnt/ total 17 drwx------ 2 root root 12288 Jan 14 17:16 lost+found -rw-r--r-- 1 root root 1601 Nov 19 13:45 passwd -r-------- 1 root root 994 Nov 19 13:45 shadow [root@centos ~]# umount /mnt/ [root@centos ~]# drbdadm secondary web
服务器B:
[root@centos1 ~]# drbdadm primary web --将从设备设置为主设备 [root@centos1 ~]# mount /dev/drbd0 /mnt/ --挂载 [root@centos1 ~]# ll /mnt/ --查看文件存在 total 17 drwx------ 2 root root 12288 Jan 14 17:16 lost+found -rw-r--r-- 1 root root 1601 Nov 19 13:45 passwd -r-------- 1 root root 994 Nov 19 13:45 shadow [root@centos1 ~]#
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