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This article mainly introduces "the basic introduction and advanced usage of rsync under linux". In daily operation, I believe many people have doubts about the basic introduction and advanced usage of rsync under linux. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about "basic introduction and advanced usage of rsync under linux". Next, please follow the editor to study!

Rsync Foundation

I manage binary repositories for a global organization with about 35000 developers and dozens of TB files. I often move or archive hundreds of GB of data at a time. Rsync is used. This experience makes me full of confidence in this simple tool. So, yes, I use it at home to back up my Linux system.

The basic rsync command is simple.

Rsync-av source directory destination directory

In fact, the rsync commands taught in various guides work well in most general situations. However, suppose we need to back up a large amount of data. For example, a directory containing 2000 subdirectories, each containing data from 50GB to 700GB. Running rsync in this directory can take a lot of time, especially if you use the check option (I prefer to use it).

We may encounter performance problems when we try to synchronize large amounts of data or through slow network connections. Let me show you some of the methods I use to ensure good performance and reliability.

Advanced usage of rsync

The first line that appears during the rsync runtime is: "sending a list of incremental files." If you search for this line online, you'll see a lot of similar questions: why it keeps running, or why it seems to hang up.

Here is an example based on this scenario. Suppose we have a directory of / storage and we want to back up to an external USB disk, we can use the following command:

Rsync-cav / storage / media/WDPassport

The-c option tells rsync to use a file checksum instead of a timestamp to determine the changed file, which usually takes longer. To decompose the / storage directory, I synchronize through subdirectories, using the find command. This is an example:

Find / storage-type d-exec rsync-cav {} / media/WDPassport\

This looks fine, but if there are any files in the / storage directory, they will be skipped. So how do we synchronize the files in the / storage directory? There is also a slight difference that these options will cause rsync to synchronize. Directory, which is the source directory itself; this means that it synchronizes the subdirectories twice, which is not what we want.

To make a long story short, my solution is a "double-incremental" script. This allows me to break down a directory, for example, when your home directory has multiple large directories, such as music or family photos, decompose the / home directory into a single user home directory.

This is an example of my script:

HOMES= "alan" DRIVE= "/ media/WDPassport" for HOME in $HOMES; docd / home/$HOMErsync-cdlptgov-delete. / $DRIVE/$HOMEfind. -maxdepth 1-type d-not-name "."-exec rsync-crlptgov-- delete {} / $DRIVE/$HOME\; done

The first rsync command copies the files and directories it finds in the source directory. However, it leaves directories unprocessed, so we can iterate over them through the find command. This is done by passing the-d argument, which tells rsync not to recurse directories.

-d,-- dirs transfers directories without recursion

The find command then passes each directory to run rsync separately. Rsync then copies the contents of the directory. This is done by passing the-r parameter, which tells rsync to recurse the directory.

-r,-- recursive recursively enters the directory

This keeps the incremental files used by rsync at a reasonable size.

Most rsync guidelines are for ease of use of the-a (or archive) parameter. This is actually a compound parameter.

-a,-- archive archiving mode; equivalent to-rlptgoD (no-Hmam talk A meme X)

The other parameters I pass are contained in a; these are-l,-p,-t,-g, and-o.

-l,-- links copy symbolic links as symbolic links-- p,-- perms reserved permissions-t,-- times retain modification time-g,-- group reserved groups-o,-- owner reserved owners (for Super Admin only)

The-- delete option tells rsync to delete any files in the destination directory that do not exist in the source directory. In this way, the result of running is just replication. You can also exclude the .trash directory or the .DS _ Store file created by MacOS.

-not-name ".Trash *"-not-name ".DS _ Store"

Be careful

One last suggestion: rsync can be a destructive command. Fortunately, its wise creator provided the ability to "fly by air". If we add the n option, rsync displays the expected output but does not write any data.

`rsync-cdlptgovn-- delete. At this point, the study of "basic introduction and advanced usage of rsync under linux" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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