SOHO Backups?

[Jim Kuzdrall]

> However, I hear CD-ROM is unreliable even over 12 months, so that's
> out.

    I have heard this too.  Does anyone know the physical mechanism 
responsible for the deterioration?  I seem to associate the tale with a 
study at a library, and the CDROMs being scratched by handling.  If 
that is the mechanism, it is irrelevant for SOHO.

> Anyone else have a different idea for backups or is tape still the
> thing?

    If we are discussing SOHO as opposed to a multiuser business, the 
backup size is smaller and the needs simpler.  My disk image is about 
9GB uncompressed.

    I based my backup on hardware failure mechanisms tempered by their 
probability of occurrence.  Convenience was another goal.  In addition, 
off-site storage is essential for fire, flood, civil disorder, moth 
cocoons, etc.

    The first backup is a clone disk that gets an rsync daily.  Two hard 
drives are unlikely to fail simultaneously.  The working drive is on 
the SCSI bus and the clone is on the IDE bus.  If one drive or bus 
fails, I can boot the alternate drive.  (I don't rsync the /etc 
or /boot directories.)  That drive is handy because it retains all the 
moved directories, deleted files, renamed files, etc.

    A partition on the IDE drive holds the 2d and 3rd backup.  A tar 
incremental is done each night.  Every 4 weeks (not every month) I do a 
tar image of the working drive to the IDE drive and to a DDS-3 tape.   
A bash script and cron get it all done.

    The tape goes to the safe deposit box, of course.  The cheap boxes 
at my bank are not wide enough for a CDROM, but a bare 3.5" or 2.5" 
drive would fit.

    I bought the DDS-3 tape drive when I knew even less about "big 
computers" than I do now.  I rather like it.  The DDS-3 tape is easy to 
carry around.  Operation is trouble free.  Every so often I will notice 
the tape has ejected, so I put in the next of the 14-tape rotation.

    One seemingly sensible tip is "Don't compress the stored data".  One 
missed bit in a compressed file propagates over a lot of data.  Of 
course, if it is a binary executable, you are screwed either way.

    So what gives with CDROMs?  I was going to store a picture inventory 
for fire and theft insurance on mini-CDROMs in my safe deposit box.

Jim Kuzdrall