On Fri, Oct 24, 2003 at 08:55:16AM -0700, Dege, Robert C. wrote: > > Thanks for the info Paul (and Jay). > > > Paul, a few additional questions directed towards your response. > > > In my experience the compress best uses 4 times as much CPU for only > > 5% better compression, so it's not worth it, unless you have spare CPU > > cycles to burn. Maybe it's better to increase the dumpcycle (maybe > > Is this 5% difference you're referring to between compress-fast vs. > compress-best?
I've done similar measurements to Paul's and while I found a bigger difference between --fast and --best (aka -1 and -9 with 7 more gradations between) it was not huge. And yes, we are refering to compression of say 45% reduction with --fast vs say 55% with --best. But as Paul indicates with a 4x (I saw 5x) increase in cpu usage. What I also found was the writers of gzip picked a default of -6 which in my tests gives the bulk of the increased compression for only about 1.8x cpu usage compared to -1. The improvements in compression at levels -7, -8, and -9 were tiny for the increased cpu usage. > > Right. If you think a litter more about this, the amanda server does > > not need to be the computer that runs smbclient. My amandaserver has > > already his cpu fully loaded, and two other machines do the smbclient > > backups for my window machines, and they do the compression too. > > > How could I offload the smbclient connections through another machine? Are > you implying an smbmount on the client, or is there some trick with > smbclient that I'm not thinking of right now? If hostA is the amanda tape server (also its own client possibly) you probably have disklist entries like "hostA //pchost/xyz". But if you have other unix systems that can do samba too (say hostB), just change the quoted string to use hostB instead of hostA. If hostB does client-side compression then the compression burden is offloaded from hostA to hostB. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road (609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)
