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Once you have installed the cogofs RPM to your system, you can try to load the kernel module by using the modprobe command, for example:
modprobe cogofs
You can then use the lsmod command to check if the cogofs module is loaded, for example lsmod might show you:
cogofs 132128 0 (unused) compeng 56928 0 [cogofs] 8139too 14400 2 ext3 61312 6 jbd 40440 6 [ext3] |
The module, 'compeng' is the Kypertec compression engine used by cogofs module. This will be loaded automatically whenever cogofs is loaded. If cogofs module fails to load, it is most likely that you don't have an appropriate cogofs license installed. Please check your syslog messages, if this is the case, please see Section 2.1 for more details.
In general, cogofs is a stackable file system working like this:
+--------------------------+ | /mnt/cogo/abc.txt | <- Cogofs mounted filesystem +--------------------------+ | /cogofs/src/abc.txt.cogo | <- Lower filesystem contains the Cogofs +--------------------------+ compressed file |
From the above diagram, when you access abc.txt on /mnt/cogo directory, the content of it will be transparently decompressed or compressed by Cogofs, it presents like a normal file. However, the actual file is being stored in /cogofs/src directory is always in compressed form. When a new file is created on /mnt/cogo directory, Cogofs will automatically compress the data and store the file in the lower fs with the .cogo extension appended to the original filename.
To try out, you can use the mount command to mount /cogofs/src ( assume this directory is created ) to /mnt/cogo, for example:
$ mount -t cogofs -o fs=/cogofs/src none /mnt/cogo |
The fs=[dir] option tells cogofs the source location ( lower file system ) to be used. none is passed to the mount command as cogofs is not a block device file system. The last entry, /mnt/cogo tells cogofs to mount /cogofs/src to /mnt/cogo. If mount command does not return any error, Cogofs is ready to go and you can try it.