Dan Langille wrote (2015/12/02): > I had not considered that. In my case, I backup to local HDD (ZFS array) > for long term storage. Right after those jobs finish, I copy to tape. > Sounds like I need to implement spooling now. Fortunately, my full > backups are only about 400GB. I think I can get away with one SSD > feeding my LTO-4.
Hello Dan, if you have just one stream at a time, either read stream or write stream like in this case, things are not so bad with rotational disks. In this case, you can count almost with read/write speed of the disk. However do not forget, that nominal speeds are true just at the beginning of the disk. When datas are read from the end of the disk, typical speed is about half of the nominal. So if you have disk with nominal 160 MB/s speed, datas from the end of the disk could be read typically just at 80 MB/s. SSDs are needed in case there are more data streams at a time, for examle if five jobs are spooled (five write streams) and one job is despooled to the tape (one read stream) at the same time. Then, disks have to reposition too often and performance drops too much. iostat and gstat (FreeBSD) are your friends ;o) Very important is %busy in gstat. If the value is red when writing to the tape, then try SSD (very simplified). -- Rudolf Cejka <cejkar at fit.vutbr.cz> http://www.fit.vutbr.cz/~cejkar Brno University of Technology, Faculty of Information Technology Bozetechova 2, 612 66 Brno, Czech Republic ------------------------------------------------------------------------------ Go from Idea to Many App Stores Faster with Intel(R) XDK Give your users amazing mobile app experiences with Intel(R) XDK. Use one codebase in this all-in-one HTML5 development environment. Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs. http://pubads.g.doubleclick.net/gampad/clk?id=254741911&iu=/4140 _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
