I think this bug is actually in glibc or something similar,
rather than tar. Prior to upgrading to RedHat 5.0, we saw
nice speedy transfers at 15-20 MB/min, afterward they
have slowed to about 3 MB/min.
The context is this: a SCSI 4-mm tape drive is located on
an Alpha OSF 4.0E host. From that host we use ssh or rsh
(doesn't matter which for this problem) to connect to a
Linux host, which then runs tar with output to a filespec
of the form osfhost:/dev/tape. The network is a 10 Mbs
ethernet (mix of thinwire and CAT-5 UTP). The Linux hosts
have a variety of NICs: tlan, ewrk3, eepro100, so it does
not seem to be a driver problem.
The same OSF host can back up another OSF host or an AIX
host on the same local network at 15-20 MB/min, which is
close to the limit set by the tape speed.
We do not see any abnormal network-related messages in
the logs on either host during the transfer.
File transfers via NFS or ftp go at the normal high rate,
limited only by network bandwidth. The slowness only
shows up when using tar.
we never were able to duplicate this. If you are still having problems, or the
problem was not solved in 6.1, please reopen the bug.