Wanted: fast tar across ether

[Bob Sutterfield]

In article <1430 at gould.doc.ic.ac.uk> lmjm at doc.ic.ac.uk (Lee McLoughlin) writes:
   I am in urgent need of a way to write tar output to a remote tape
   drive, an exabyte, over ethernet very quickly - preferably allowing
   the exabyte to stream.  I currently use the gnu-tar, which does a
   pretty good job but I really something faster.

This SparcStation-1 has a local Wren-VI and an Exabyte on the same
SCSI bus, and I use GNU Tar for backups of it and several other
machines.  I can get about 30% better throughput when backing up the
local disk than when backing up a disk attached to a 4/110 on the same
Ethernet, but even the local speed is about 40% short of what the
Exabyte specs say would cause it to stream.

Paul Placeway did some improvements to dump while he was at Ohio State
and was (I believe) able to drive tapes at device speed either locally
or across an Ethernet.  The improvements involved some nifty
sliding-window acknowledgement schemes.  You'd need to do something
similar if you intend to make tar much faster.