SUMMARY: Slow transfers on remote backup

From: James Rae (
Date: Thu Sep 09 1993 - 04:14:59 CDT

Sun Managers
My original question was as follows:
>Hello Sun Managers,
> I am using tar to back-up a large file system in a remote site (actually
>4 states away) via a T1 connection and my question is this. Does anyone
>know the optimum settings for the tar command to maximize transfers across
>a T1 connection. I have almost 3GB of data and at the present it takes just
>short of 10 hours to complete the backup. I'm running out of night, if you
>know what I mean. I would be happy to summarize, of course!!

Thanks to: (Sumner Hushing)
Charles A Finnell <> (Ken Marshall) ( Steven Horn) (Jay Lessert) (Jim Carroll ) (James Terry) (Andy Feldt)
kmah@DCS-Systems.COM (Kevin Mah) (Larry Freeman) (Peter Samuel) (Peter Gutmann) (Birger A. Wathne)
Roland Kaltefleiter <> (Joel Shandelman) (Thomas J Davis)

Most people suggested that I use compress to reduce the amount of data that
I have to send through the line using a comand similar to:

rsh remote 'cd /filesys; tar cf - . | compress' | uncompress | tar xf -
or (if any kind of blocking control can affect performance)
rsh remote 'cd /filesys; tar cf - . | compress | dd bs=xyz' | uncompress | tar xf -

I am presently testing this with limited success (about 14% increase in
performance on my initial benchmarks).

Also a special thanks to Ken Mashall ( for sending me a copy
of the buffer program. I haven`t had a chance to try it yet but it is my
next project.

| James Rae | |
| Systems Administrator | Internet: |
| New Venture Gear | Phone: (313)524-5548 |
| 1775 Research Dr. | Fax: (313)524-5570 |
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