Craig White schrieb: > On Wed, 2009-01-07 at 17:57 +0100, Ralf Gross wrote: > > T. Horsnell schrieb: > > > Ralf Gross wrote: > > > > Ferdinando Pasqualetti schrieb: > > > >> I think you should use /dev/random, not /dev/zero unless hardware > > > >> compression is disabled in order to have more realistic figures. > > > > > > > > This wouldn't be a good idea, /dev/random or /dev/urandom are just too > > > > slow in generating random data. To test the nativ speed of the drive > > > > creating a file from /dev/urandom and writing this file then from > > > > tmpfs or a fast disk to the drive would be much better. > > > > > > > > > > > > Ralf > > > > > > Personally, I'd use /dev/zero with compression turned off. > > > Then there's *nothing* between the data-source and the tapedrive. > > > > Yes, but most people use hardware compresion with LTO drives. Sooner > > or later he has to test the drive with compression. > ---- > funny thing is that amanda developers are adamant that you disable > hardware compression and use software compression instead.
With Bacula and LTO-4 drives I get 80 MB/s and a compression rate of 1,4:1. It would be fun to backup several TB with gzip compression. > Obviously it takes longer and more cpu power to compress the files in > software before storing them on the tape and if you leave hardware > compression on and use software compression too, the files probably grow > in size. Not with LTO drives. http://en.wikipedia.org/wiki/Linear_Tape-Open#LTO-DC > Commercial backup software just seems to always use hardware > compression. Which is not the worst idea. Ralf ------------------------------------------------------------------------------ Check out the new SourceForge.net Marketplace. It is the best place to buy or sell services for just about anything Open Source. http://p.sf.net/sfu/Xq1LFB _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
