Linux uses rsync to implement file directory synchronization

To achieve the goal:
Server A synchronizes with Server B, which only indicates that server a synchronizes to Server B and Server B restores to server A.
Consider security factors and synchronize with ordinary users.
Using Cronjob, timed synchronization.

A/opt/web directory on server A, synchronizing with/opt/web directory on B client server. That is: B actively synchronized with a. (A's files are synchronized to the B machine)

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Os:reaht AS4 A Server 192.168.0.100/opt/web B Server 192.168.0.60/opt/web

A. A Server config

1. Installation Services

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Yum Install xinetd Yum Install rsync

2. Vi/etc/xinetd.d/rsync modifies disable =yes as disable =no, with the following revised documents

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# Default:off # description:the Rsync server is a good addition to a FTP server, as it # allows CRC Checksumming etc. Service rsync { Disable = no Socket_type = Stream wait = no user = Backup Server =/usr/bin/rsync Server_args =–daemon Log_on_failure + + USERID }

3. Edit Primary profile/etc/rsyncd.conf (Create yourself if not present)

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Vi/etc/rsyncd.conf UID = Backup GID = Backup Use chroot = no # chroot not used Max connections = 4 # Maximum number of connections is 4 PID file =/var/run/rsyncd.pid Lock file =/var/run/rsyncd.lock Log file =/var/log/rsyncd.log # logging Files [web] # Here is the Certified module name, which needs to be specified on the client side Path =/opt/web # A directory that needs to be mirrored Ignore errors # can ignore some irrelevant IO errors Read Only = true # reading only List = False # does not allow column files Hosts allow = 192.168.0.0 # allowed IP address Hosts deny = 0.0.0.0/32 # banned IP address Auth users = backup # authenticated username, if this line is not found, it is anonymous Secrets file =/etc/backup.pass #认证用户的密码文件 Authentication file name

4. Edit server password file/etc/backup.pass, file can only have Read permission 400

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Vi/etc/backup.pass #文件格式如下 backup:123456 chmod 400/etc/backup.pass

5. Start Service
Start rsync for the first time

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Rsync–daemon–config=/etc/rsyncd.conf

If prompted

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Failed to create PID File/var/run/rsyncd.pid:file exists

Using directives

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Rm-rf/var/run/rsyncd.pid

Use the following command to see if Rsync is already running: Netstat-an|grep 873

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[Root@localhost web]# Netstat-an|grep 873 TCP 0 0 0.0.0.0:873 0.0.0.0:* LISTEN TCP 0 0::: 873:::* LISTEN

Reboot already running rsync

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[root@mail video]# Ps-ef | grep rsync root     27284     1  0 10:26?   00:00:00 rsync– daemon–config=/etc/rsyncd.conf root     30516 29986  0 18:35 pts/3    00:00:00 grep rsync [root@mail video]# kill-9 27284 [root@mail video]# rsync–daemon–config=/etc/rsyncd.conf Service xinetd Restart, restart the xinted service Rsync system, it needs to be started with a –deamon mode, and the services port is TCP 873 Rsync–deamon–config=/etc/rsyn cd.conf

There are several different ways to start a service at startup, such as:
A, join inetd.conf
Edit/etc/services, add rsync 873/tcp, specify the service port for Rsync is 873
Add/etc/inetd.conf, join rsync stream TCP nowait backup/bin/rsync Rsync–daemon
B, Join rc.local
In a variety of operating systems, RC file storage location is not the same, you can modify the system to boot when the Rsync–daemon loaded in.

Two. B Server config
1. Yum Install rsync installation rsync service
2. Create an rsync connection when the password file/etc/rsync_client.pass, the listing of their own random arrangement, file permissions for read-only 400
Vi/etc/rsync_client.pass #文件格式如下:
#只需要配置连接时使用的密码即可, you must be the same as the password defined on server A.

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chmod 400/etc/rsync_client.pass

3. Use the rsync command to connect to the server to achieve file synchronization

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Rsync-vzrtopg–progress–delete–password-file=/etc/rsync_client.pass Backup@192.168.0.100::web/opt/web

PS: When directory synchronization to save the same file owner information, you need to create the same user on the B server

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Rsync-qcazrtopgl–progress–delete–password-file=/etc/rsync_client.pass–exclude= "*.gz" –exclude-from=/opt/pcdir Backup@192.168.0.100::web/opt/web

Backup is a certified user name;
192.168.0.100 for server-side IP;
The Web is a module name;
/opt/web as a local directory
Three Timed tasks

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[Root@localhost admin_backups]# VI backup.sh

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#/bin/sh Rsync-qcazrtopgl–progress–delete–password-file=/etc/rsync_client.pass–exclude= "*.gz" –exclude-from=/opt/pcdir Backup@192.168.0.100::web/opt/web

To add a timed task:

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[Root@localhost admin_backups]# Crontab–e

Add the following:

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*/1 * * * */home/admin/admin_backups/backup.sh >/dev/null 2>&1

Sync every minute from server A to Server B!
4. Use –execlude= to exclude file suffix names that do not need to be synchronized

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Rsync-vzrtopg–progress–delete–password-file=/etc/rsync_client.pass–exclude= "*.tmp"

Backup@192.168.0.100::web/opt/web
5. Use –execlude-from= to exclude directories that do not need to be synchronized

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[root@localhost opt]# Rsync-vzrtopg–progress–delete–password-file=/etc/rsync_client.pass–exclude-from=/opt/pcdir Backup@192.168.0.100::web/opt/web

The contents of the

/opt/pcdir file are as follows
Cat/opt/pcdir
temp/
Parameter Description
-VZRTOPG
V is verbose,
Z is compression,
R is recursive,
Topg is to keep the original properties of the file, such as the owner, the time parameter
--progress
is to show detailed progress
–delete
means that if the server side deletes this file, then the client also deletes the file accordingly, maintaining true consistency
–exclude= "*.tmp"                Does not contain some files
–execlude-from=        exclude directories that do not need to be synchronized
/opt/web/
Specify the client side store mirror destination path