Taper FAQ: Problems backing up

5. Problems backing up

5.1 Whenever I try to select a file or directory for backup, I get the error message tt File is on exclusion list/.

You have extraneous spaces in your exclude directory and/or exclude files preferences. There must be no leading or trailing spaces in the preferences. Additionally, each file/directory (if any) entry must be separated by one space only.

5.2 I am mid-way through backing up in the directory /proc and I get funny messages such as `-7% done` and the program seems to hang?

The /proc directory does not contain files. It contains run-time system information, such as the environment of running processes, an image of system memory etc.. Therefore, you should not need to backup the /proc directory. If you do, you will get spurious results such as the above. See TAPER.TXT for how to automatically exclude the /proc system.

5.3 When doing backups that take more than one tape, when it reaches the end of the tape, taper segmentation faults.

Taper can't correctly work out the end of tape on some tape drives. If the above occurs with you, your tape drive is one of those. Go to the preference menu, and under tape drive preferences, tell taper the size of your tape drive. Note that taper needs the UNCOMPRESSED size of the tape drive. Subtract about 10% from the manufacturers stated to account for formatting etc.. (eg. if your tape drive is 120MB, tell taper it is 108MB).

5.4 After doing a backup or mkinfo, taper exists saying `Unable to create info file`.

Check that taper is able to create the info file directory (the default is /$HOME/.taper_info). If it can't, taper generates this error. Reasons include no disk space, and you don't have permission to. Note that after this error, the backup is still intact. You just have to fix the problem and then select mkinfo, not do the whole backup again.

5.5 Taper works fine in interactive mode, but when I run it from a cron job, I get a `Can't start backup child` error mailed to me.

As explained above, taper uses two ancillary program. Note that cron uses a different path than the normal one. Generally, it is only /bin, /usr/bin and /usr/local/bin.

Either copy bg_backup and bg_restore to one of those directories, or make links in these directories or change the path.

5.6 Taper says `Can't start backup child`.

Taper uses two ancillary programs, bg_backup and bg_restore to handle background compression. Make sure that you have these two programs, and that they are in the directory you started taper in or in a directory on your path.

5.7 Taper says `Can't start backup child` when running under a cron job.

For some installations, cron does not have /sbin and /usr/sbin in its search path. I don't know why. The solution is to put bg_backup, bg_restore and taper in /usr/bin or /usr/sbin.

5.8 I notice that zftape has a compressed mode. Should I use taper compression or zftape compression

If you use zftape compression, you may find your backups will be quicker, and they certainly will be easier on system load. However, should a segment of tape become corrupted, then it will be virtually impossible to reconstruct your backup and retrieve any files beyond the corrupted segment.

If you use taper's compression, however, it may be possible to retrieve data beyond the corrupted section, depending on exactly which pieces of data were corrupted. This is because taper compresses each file individually and hence, the corruption won't affect other files.

5.9 Why does taper seg fault at the end of a backup or while updating the header files.

There seems to be a bug in either libc 5.3.12 and/or binutils 2.6.0.12. To find out what version of libc you are using, do a


   ls -l /lib/libc.so.5

and you will see what version of libc you are using.

To find out what version of binutils you are using, do a


   ld -v

which will print your version.

If you are using one or both of the above, then you can do one of the following:

Downgrade your C libraries to 5.2.18
Upgrade your binutils to 2.6.0.14

Option 2 is the easier (and more logical choice), however, it may not work all the time. Option 1 should always work.

5.10 Why is taper not compressing my files even though I have compression turned on?

The most common cause is that taper cannot find bg_backup which is the program that compresses programs in the background. Make sure that you have this program compiled and either in the current directory or on your path.

5.11 I am using ftape version 3 and getting some spurious results.

ftape version 3 is actually a combination of the old ftape and zftape. Therefore, if you are using ftape version 3, you should start taper with the zftape option (ie. taper -T z).

5.12 I am running from a cron job and keep on getting mailed errors about not being able to start a backup child. It works fine from the command line.

For some reason, when cron runs a job, it doesn't put /sbin on the path, and therefore, taper can't find its children which are in /sbin. The solution is to move taper, bg_backup and bg_restore to /bin or put links in /bin to point to the entries in /sbin. Newer versions of taper will automatically do this with make install.