Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!mstar!mstar.morningstar.com!bob From: bob@MorningStar.Com (Bob Sutterfield) Newsgroups: comp.unix.wizards Subject: Re: Wanted: fast tar across ether Message-ID: Date: 10 Jan 90 21:12:56 GMT References: <1430@gould.doc.ic.ac.uk> Sender: news@MorningStar.COM (USENET Administrator) Reply-To: bob@MorningStar.Com (Bob Sutterfield) Organization: Morning Star Technologies Lines: 18 In-reply-to: lmjm@doc.ic.ac.uk's message of 10 Jan 90 02:02:18 GMT In article <1430@gould.doc.ic.ac.uk> lmjm@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.