When using SSH with the Filesystem Backup module, the destination host must have rmt installed, and must also have bzip2 installed if it is used for compression. However, Linux distros like RHEL/CentOS are often installed with a "minimal" image now, which does not include either of these by default. Webmin does not check for them, which causes confusion when attempting to run a backup for the first time.
In the case of missing rmt, both dump and tar appear to be working, and they consume resources on the host, but they are not able to write any data. There is no error displayed in Webmin. It would be much more user friendly if the backup script could check for this before running the backup.
In the case of missing bzip2, the backup appears to complete, but it is not able to use compression. This is confusing especially when the filename has a bz2 extension but cannot be read by bzip2. It also causes this error when verifying with the Webmin module:
. complete. Now verifying backup ..
bzip2: (stdin): trailing garbage after EOF ignored
.. backup complete.
1) After performing a backup with TAR, the link at the bottom indicates: "Return to dump". This should say "Return to backup".
2) In .../help.cgi/fsdump/dest - Backup to ... For backups to a remote host to work, it must support the rsh protocol, which is not usually turned on by default for security reasons.
This is not correct. There is no mention of SSH here, which is the preferred replacement for RSH.
3) In .../help.cgi/fsdump/rsh - Remote backup command ... SSH will only work if the root user's SSH configuration allows passwordless logins from this system to the remote server.
This is not correct. SSH will work fine if a username and password are entered.
These are just a few examples. I'm sure there are other similar cases, but I didn't check them all....