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It is believed that many inexperienced people don't know what to do about data synchronization and file incremental backup in rsync server erection. Therefore, this paper summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

In order to achieve load balancing among multiple servers, we need to synchronize data among these servers, and rsync software is also competent. Let's introduce how to set up a rsync server to achieve the function of file incremental backup and data synchronization.

What is rsync?

Rsync is a fast incremental file transfer tool that can be used for backup within the same host, and we can also use it as a network backup tool for different hosts. This article is mainly about how to set up a rsync server to realize file transfer, backup and mirroring. Compared with tar and wget, rsync also has its own advantages, such as high speed, security and efficiency.

Installation of rsync

On the CentOS server, we can execute the following command to install

Yum install rsync

For debian, ubuntu servers, the following command

Sudo apt-get install rsync

Configuration file rsyncd.conf for rsync server

Next we will cover three files, rsyncd.conf,rsyncd.secrets and rsyncd.motd.

Rsyncd.conf is the main configuration file for the rsync server.

Rsyncd.secrets is the password file that logs in to the rsync server.

Rsyncd.motd defines the rysnc server information, that is, the user login information.

Let's set up these three files respectively.

Mkdir / etc/rsyncd

Note: create a rsyncd directory under the / etc directory, which we use to store rsyncd.conf and rsyncd.secrets files

Touch / etc/rsyncd/rsyncd.conf

Note: create a rsyncd.conf, which is the configuration file for the rsync server

Touch / etc/rsyncd/rsyncd.secrets

Note: create rsyncd.secrets, which is the user password file

Chmod 600 / etc/rsyncd/rsyncd.secrets

Note: for the security of the password, we set the permission to 600

Touch / etc/rsyncd/rsyncd.motd

Note: create a rsyncd.motd file, which is a file that defines server information.

It's time for us to modify the rsyncd.conf and rsyncd.secrets and rsyncd.motd files next.

Contents of rsyncd.conf file:

The code is as follows:

# Minimal configuration file for rsync daemon

# See rsync (1) and rsyncd.conf (5) man pages for help

# This line is required by the / etc/init.d/rsyncd script

Pid file = / var/run/rsyncd.pid

Port = 873

Address = 192.168.1.171

# uid = nobody

# gid = nobody

Uid = root

Gid = root

Use chroot = yes

Read only = yes

# limit access to private LANs

Hosts allow=192.168.1.0/255.255.255.0 10.0.1.0/255.255.255.0

Hosts deny=*

Max connections = 5

Motd file = / etc/rsyncd/rsyncd.motd

# This will give you a separate log file

# log file = / var/log/rsync.log

# This will log every file transferred-up to 85000 + per user, per sync

# transfer logging = yes

Log format =% t% a% m f% b

Syslog facility = local3

Timeout = 300

[linuxsirhome]

Path = / home

List=yes

Ignore errors

Auth users = linuxsir

Secrets file = / etc/rsyncd/rsyncd.secrets

Comment = linuxsir home

Exclude = beinan/ samba/

[beinan]

Path = / opt

List=no

Ignore errors

Comment = optdir

Auth users = beinan

Secrets file = / etc/rsyncd/rsyncd.secrets

Password file: content format of / etc/rsyncd/rsyncd.secrets

User name: password

Linuxsir:222222

Beinan:333333

Note: the password here is worth noting. For the sake of security, you can't write the password of the system user here. For example, your system user's linuxsir password is abcdefg. For security, you can make the linuxsir in rsync to be 222222. This is similar to the password principle of samba user authentication.

Rsyncd.motd file

It defines rysnc server information, that is, user login information. For example, let the user know who provided the server; similar to the jb51.net ftp we see when the ftp server logs in. Of course, this is not necessary when defining variables globally, you can write out or delete it with the # sign; I wrote a rsyncd.motd here as follows:

+ +

+ jb51.net rsync 2002-2007 +

+ +

Rsyncd.conf file code description

Pid file = / var/run/rsyncd.pid

Note: tell the process to write to / var/run/rsyncd.pid file

Port = 873

Note: specify the running port. The default is 873. You can specify it yourself.

Address = 192.168.1.171

Note: specify the server IP address

Uid = nobody

Gid = nobdoy

Note: when transferring files on the server side, which user and user group should be sent for execution? the default is nobody. If you use nobody users and user groups, you may encounter permission problems, and some files cannot be pulled from the server. So I slacked off and used root for convenience. However, you can resolve permissions by specifying users in the modules defined when defining directories to synchronize.

Use chroot = yes

With chroot, the server daemon sends chroot to a directory in the file system before transferring the file, which has the advantage of protecting the system from installation vulnerabilities. The disadvantage is that superuser privileges are required. In addition, symbolic link files will be excluded. That is to say, if you have a symbolic link on the rsync server, when you run the client's synchronization data on the backup server, you will only synchronize the symbolic link name, not the contents of the symbolic link; you need to try this yourself.

Read only = yes

Note: read only is a read-only option, that is, clients are not allowed to upload files to the server. There is also a write only option, try to do what it is for

# limit access to private LANs

Hosts allow=192.168.1.0/255.255.255.0 10.0.1.0/255.255.255.0

Note: you can specify either a single IP or the entire network segment, which can improve security. The format is to be separated by spaces between ip and ip, ip and network segments, and network segments.

Max connections = 5

Note: maximum number of client connections

Motd file = / etc/rsyncd/rsyncd.motd

Note: motd file defines the server information and writes the contents of the rsyncd.motd file by yourself. Users will see this message when they log in.

Log file = / var/log/rsync.log

Note: log of rsync server

Transfer logging = yes

Note: this is the log of the transferred file.

[linuxsirhome]

Note: module, which provides us with the name of a link, where to link to, in this module, link to the / home directory; use [name] form

Path = / home

Note: specify the location of the file directory, which must be specified

Auth users = linuxsir

Note: the authenticated user is linuxsir and must exist on the server.

List=yes

Note: list means to list the directories on the rsync server that provide synchronous data on the server whether the module is displayed or not. The default is yes. If you don't want to list it, no it; if no is more secure, at least others don't know which directories are available on your server. You just need to know it yourself.

Ignore errors

Note: ignore IO error, please check the documentation for details

Secrets file = / etc/rsyncd/rsyncd.secrets

Note: which file does the password exist

Comment = linuxsir home data

Note: comments can be defined by yourself, you can write anything, just write something related.

Exclude = beinan/ samba/

Note: exclude means to exclude, that is, to exclude beinan and samba under the / home directory; there is a space between the beinan/ and samba/ directories

Start the rsync server and firewall settings

Start the rsync server

Starting the rsync server is fairly simple.-daemon is to let rsync run in server mode.

/ usr/bin/rsync-daemon-config=/etc/rsyncd/rsyncd.conf

Rsync servers and firewalls

The Linux firewall uses iptables, so we should at least let your defined rsync server port through on the server side and on the client side.

Iptables-An INPUT-p tcp-m state-- state NEW-m tcp-- dport 873-j ACCEPT

Check to see if the firewall has port 873 open

Iptables-L

Synchronize data through the rsync client

Rsync-avzP linuxsir@jb51.net::linuxsirhome linuxsirhome

Password: enter the password of linuxsir here, which is provided by the server. In the previous example, we used 222222, and the password entered is not shown. Enter enter after typing.

Note: this command means that you log in to the server with the linuxsir user and synchronize the linuxsirhome data to the local directory linuxsirhome. Of course, you can define the local directory, such as linuxsir; when you are on the client, there is no linuxsirhome directory under the current operation directory, the system will automatically create one for you; when it exists in the linuxsirhome directory, you should pay attention to its write permission.

Description:

-a parameter, equivalent to-rlptgoD,-r is recursive-l is a linked file, meaning to copy a linked file;-p means to keep the original permissions of the file;-t to keep the original time of the file;-g to keep the original user group of the file;-o to keep the original owner of the file;-D is equivalent to the block device file.

-z compression during transmission

-P transmission progress

The progress of-v transmission and other information has something to do with-P, try it yourself. You can read the document.

Rsync-avzP-- delete linuxsir@jb51.net::linuxsirhome linuxsirhome

This time we introduce a-delete option, which means that the data on the client side should be exactly the same as the server side, and if there are files in the linuxsirhome directory that do not exist on the server, delete them. The ultimate goal is to keep the data on the linuxsirhome directory exactly the same as on the server; be careful when using it, it is best not to use the directory that already has important numbers as a local update directory, otherwise all your data will be deleted

Rsync-avzP-delete-password-file=rsync.password linuxsir@jb51.net::linuxsirhome linuxsirhome

This time we added an option-password-file=rsync.password, which means that when we log in to the rsync server to synchronize data as a linuxsir user, the password will read the rsync.password file. The content of this file is only the password of the linuxsir user. We need to do the following

The code is as follows:

Touch rsync.password

Chmod 600 rsync.password

Echo "222222" > rsync.password

Rsync-avzP-delete-password-file=rsync.password linuxsir@jb51.net::linuxsirhome linuxsirhome

Note: this eliminates the need for a password; in fact, this is more important, because it is necessary for the server to schedule tasks through crond

Let the rsync client automatically synchronize data with the server

Edit crontab

Crontab-e

Add the following code:

100 * rsync-avzP-delete-password-file=rsync.password linuxsir@jb51.net::linuxsirhome linuxsirhome

Indicates that the following commands are executed at 00:10 every day. For more information on crontab usage, please refer to

After reading the above, have you mastered the method of data synchronization and file incremental backup in the construction of rsync server? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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