Subject: other backup technologies?
To: None <current-users@NetBSD.ORG>
From: John F. Woods <>
List: current-users
Date: 01/05/1997 13:52:18
I corrupted the partition map of a big filesystem yesterday, and
although fsck found relatively little curdling once I got the
partition map restored properly, I decided to restore from tape,
figuring that wouldn't take ALL that long.  Oops.

The partition in question is 1.2GB, and contains around 600MB of
archived netnews articles (all stored as the original files).  I first
used tar to back it up, but that ran rather slowly (somewhat under
300KB/s).  I then tried dump, and it ran substantially faster (roughly
450KB/s).  However, when I restored the filesystem from the dump tape,
I was shocked at how slow restore is (almost 5 hours to finish the
restore, 4.5 of which was tape time, 35KB/s).  Granted, I had restore
running in verbose mode, which slowed it down somewhat, but that's
still disturbing.

Once I got the restore finished, I made a new backup tape, this time
using GNU tar's --listed-incremental feature.  And I thought restore
was slow...  that was just agonizing.  (I also appended to the backup
tape a raw dump of the filesystem, hoping for an "instant" restore
scheme; however, I just found that using "mt -f /dev/nrst0 fsf 1" to
skip the tar at the front of the tape doesn't *quite* work, because
the request times out (it takes a long time to skip several hundred
megabytes of tape...).  Fortunately, the drive just kept chugging
along until it found the filemark.)

So, my question is this: are there any backup alternatives that will
give reasonable performance for both backup and restore in this
environment?  (hundreds of megabytes, hundreds of thousands of small
files)  And while I'm thinking of it, are there any alternative storage
methods I should look into (I don't really need to store individual
files, that just makes it easy)?