[rescue] Re: intel vs. sun- for real

[Robert Novak]

On Sun, 21 Jul 2002 s at avoidant.org wrote:

> Larry Snyder wrote:
> 
> > Is there a reason you're unzipping before putting to tape?
> 
> The Exabyte does it's own compression far better than gzip does.

This is probably true, at least for time purposes. However, if you're
doing a gzip+gunzip and then writing to tape, you're wasting a lot of
time.

When I was at a small corner of a big networking and telephony company,
they were doing backups of 5 9gb disks to a DDS2 tape drive, half one
night and half the next night. We went to a Mammoth (20GB native) drive
and were able to back everything up in one night. 

I moved from sh+tar to Amanda, and found that using gzip on the server
rather than the drive's compression got me as much as 52GB on a 20GB
native tape (vs 35-40GB with the drive's compression, as I recall). The
problem was that a full backup took 2-3 days and the nightly backup ran
most of the day. This was on an Ultra 2 2300 with 512MB RAM that was doing
nfs and nameservice at the same time.

It may be outside the scope of your arrangement, but you might consider
adding disks and eliminating the gzip/gunzip step. Reducing the level of
compression in the gzip step (gzip -1 instead of gzip -9) might also save
you some time and cpu power, and cost you a bit less disk than eliminating
the gzip altogether. 

I still think you'd enjoy the E4500 or similar system, but with 72gb disks
being "pretty cheap" you may get more out of this sort of a rework rather
than replacing the machines altogether. Or at least buy some time to work
out the next step (you can always recycle the drives).

Rob

Robert Novak, Indyramp Consulting * rnovak at indyramp.com * indyramp.com/~rnovak
	"I don't want to doubt you, Know everything about you
      I don't want to sit Across the table from you Wishing I could run."