Jon,

I thought you were in Princeton. Did you move?

--Ian

On Friday 25 July 2008 14:03:52 Jon LaBadie wrote:
> On Fri, Jul 25, 2008 at 01:18:40PM -0400, Brian Cuttler wrote:
> > We have a Solaris E250 amanda server backing up two T1000 servers,
> > also Solaris, hosting Lotus Notes.
> >
> > Over time, we decided on HW compression, runs where long but they
> > completed pretty reliably at the same time every day.
> >
> > We tried an experiment, since we hadn't really tried SW compression
> > since we upgraded the client systems, we used SW-client compression
> > and removed the HW compression. Runs jumped to 22+ hours, but we where
> > not seeing the work area filled (the data was smaller, and it was taking
> > longer to get to us).
> >
> > So I increased the inparallel parameter, which of course ramped up
> > the load on the clients even further.
> >
> > The question of which version of Gzip to run arose, we had a fairly
> > old version and there is a newer-Sun version available, just didn't
> > know how version sensitive we where. I know version of gzip (which
> > we use on some partitons on these clients) is very version specific.
> >
> > Is there a list of tested/approved gzip versions ? I didn't see one
> > but may not have dug deep enough.
> >
> > Current gzip
> > $ /usr/local/bin/gzip -V
> > gzip 1.2.4 (18 Aug 93)
> >
> > Proposed gzip
> > $ /usr/bin/gzip -V
> > gzip 1.3.5
> > (2002-09-30)
> > Copyright 2002 Free Software Foundation
>
> One thing to check is whether you have specified "best" for your
> compression.  Gzip allows you to select from 9 levels of compression,
> trading cpu time (and wall time) for extra compression.  Amanda
> allows you to select "fastest" (aka level 1), "best" (level 9) or
> default which is level 6.
>
> I just ran a quick test on an 11MB text only file.  Level 9 took
> three times as long as level 1.  Yet level 1 gave 83% of the compression
> of level 9.  I like default level 6 which took 1.8 times as long
> as level 1 and gave 97% of the compression of level 9.
>
> BTW I also ran bzip2 on the same file.  It did 60% better than gzip
> level 9, but took nearly 22 times as long as gzip level 1.
-- 
Wiki for Amanda documentation: http://wiki.zmanda.com/