Hi Arno, Thanks for answering.
Arno Lehmann wrote: > Hi, > > On 3/24/2007 9:16 PM, Marc Cuypers wrote: >> Hi, >> >> I'm still using bacula 1.38.5. >> >> To prevent shoe shining (writing, rewinding, writing again) with a tape >> drive bacula uses spooling. > ... >> The spooling to the file and the writing to tape is not concurrent. Is >> there a reason for this? > > Yes, but what it boils down to is that noone implemented a buffering > scheme like using a circular buffer and filling and emptying it > simultaneously. Note that many hard disk systems have already > difficulties delivering data fast enough to allow streaming on todays > tape drives. That would get worse if, due to concurrent writes and reads > to one disk, access times increased. > >> Has this changed in later versions? > > No, not as far as I know. > >> Are there >> any changes to be expected in this? > > I doubt it. > >> I'm asking this because backups without spooling are faster than those >> with spooling. Is this normal? > > It can be normal, and in most cases is. > > Overall throughput will probably increase when you run multiple > concurrent jobs. When running concurrent jobs, each job will have its own spool file in the spooling directory? And normally when a spool file fills for one job, writing to tape can begin, while the other jobs keep spooling? -- Best regards, marc Questionable day. Ask somebody something. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
