Management and usage of MFS in distributed storage System

This paper summarizes the management and usage of mfshttp://www.aliyun.com/zixun/aggregation/14305.html "> distributed storage System, including: MFS mount file system on client, MFS common operation, MFS for the garbage bin set the isolation time, MFS snapshots, MFS other commands, and so on detailed description.

1. mount file system on client

When you start a Management server and a data storage server (a data storage server is required, but it is recommended to start at least two), the client can use Mfsmount to hook up the MFS file system.

The use of Mfsmount is as follows:

MF Smount [-H master] [P port] [-s path] Mountpoint

The parameter meaning is shown in table 8-5.

Table 8-5 The function of the parameters of the Mfsmount command

When you start the Management Server process, you use a "-M" or "O Mfsmeta" option to mount an auxiliary file system Mfsmeta. The secondary file system can recover lost data in the following two areas:

The port mistakenly deletes the file from the MFS volume, and this file has passed the garbage file storage period.
In order to free up disk space and delete or move files, when you need to restore these files, the file has passed the junk file storage period.

To use the MFS secondary file system, you can execute the following command:

Mfsmount-m/mnt/mfsmeta

It is important to note that if you decide to mount Mfsmeta, you must include the following entry in the Mfsmaster mfsexports.cfg file:

*             . rw

This entry is in the original file, just remove the # in front of it.

After you mount the file system, you can perform all standard file operations, such as creating, copying, deleting, renaming files, and so on. MFS is a network file system, so the progress of the operation may be slower than the local system.

The remaining space of the MFS volume can be checked with the same method as the local file system. For example, the Execute DF command is as follows:

[Root@localhost/]# DF | grep MFS
mfsmaster:9421 85T 80T 4.9T/mnt/mfs
mfsmaster:9321 394G 244G 15IG 62%/mnt/mfs-test

Note that each file can be stored as multiple copies, in which case each file occupies much more space than its file itself. In addition, files that are deleted and are in the validity period (trashtime) are placed in a "trash bin", so they also take up space, depending on the number of copies of the file. As with other Linux/unix file systems, the data is stored until the file is closed to prevent deletion of files opened by other processes.