Chris Cruft

In all the documentation for amanda, nowhere can I find clear information as to how amanda avoids overlapping disklist entries (DLEs).  My conclusion is that amanda makes no effort to avoid them!  Instead, the burden is on the administrator and the tools that amanda uses (dump and GNU tar).  This is my synopsis of the resulting obstacle course.

1. Under Linux, dump will only process one filesystem at a time.  But it is possible to specify a subdirectory of a filesystem in a DLE (/mount_point/subdirectory).  In which case overlap would result if one DLE is a proper subset of another.  I don’t think amanda would choke on this or even signal it.
2. GNU’s tar, as invoked by amanda, does not appear to cross mount points -specifically the –one-file-system option is passed to tar.  Consequently, tar and dump should behave similarly in the sense that they confine their operation to a single file system.  As for dump, a DLE that is in fact a subdirectory of another DLE can be specified and probably not detected by amanda.

Lately amanda has been failing during the backup of Matt’s home directory due to changes in files during the backup process.  This is no shock as Matt keeps his Outlook PST file open all night receiving (spam) email.  Recently I have been reading about LVM snapshot volumes and they look they would neatly address the problem.  I would probably need to put the snapshot creation and destruction commands around the amanda backup -but that doesn’t look too hard.

Here is an excellent reference on troubleshooting Windows XP’s SNTP client:

https://www.redhat.com/archives/psyche-list/2004-January/msg00030.html

I ran a simple backup of five files and read them back.  On the two DDS drives, everything worked correctly.  On the Exabyte, tar returned an input/output error when testing the archive file.  I immediately ran the tapeinfo command and got the following:

Screen clipping taken: 07/12/2005, 09:58

I checked on the web for the meaning of the TapeAlert messages and they are not pretty.  Here is an excellent reference for TapeAlert messages:

http://docs.hp.com/en/diag/ems/dm_stape.htm

Today I completed a major overhaul of my NTP configuration. My objectives were to remove any dependencies on ducati and render the service more robust. What I ended up with was a configuration with bmw and triumph (my two ProLiant 3000s) configured symmetrically.

References:

http://www.sun.com/blueprints/0801/NTPpt2.pdf

I learned today that perhaps the Exabyte 8900 tape drive is not so sick as I first thought.  Instead, there seems to be a bizarre reaction by the drive to any density setting other than the native 0×27.  The failure can be seen with stinit and with mt:

Screen clipping taken: 06/12/2005, 17:31

When I set the density to the native 0×27 and perform a backup, it appears that everything works well.  Hmm…

I found a utility, tapeinfo, which gives some startlingly candid information about my Exabyte 8900:

# tapeinfo /dev/sg1

…

TapeAlert[3]:    Hard Error: Uncorrectable read/write error.

TapeAlert[5]: Read Failure: Tape faulty or tape drive broken.

…

Well, it was a used drive…

I have an ancient DDS drive (2GB).  It is so old, I don’t even really remember the specs.  I hooked it up to bmw (along with the Exabyte drive and the HP DDS-2 drive) and ran a backup.  But it quickly failed.  I found some references to the drive on the web, but nothing with a lot of detail.  I tried to create an stinit.def entry from the /usr/share/doc/mt-st-0.9b/stinit.def.examples file, but that did not seem to make a differences.

References:

http://www.datman.com/tbul/dmtb_014.htm

My brother bought another 35/70 tape drive -this time with a 30-day guarantee.  Sure enough, when I run the tar test, it seems fine.  Tonight I will put it through the amanda tests.

Today I easily installed the HP Library and Tape Tool.  It was a simple matter of downloading the RedHat 9 version (which appears to be a generic Linux version), untarring the file and running the installer.  After that, the program can be run with /opt/ltt/hp_ltt.

References and Useful Links:

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?pnameOID=406731&locale=en_US&taskId=135&prodSeriesId=406729&prodTypeId=12169