On Wednesday 09 June 2010 14:20:32 Wolfram Schlich wrote: > * Wolfram Schlich <[email protected]> [2010-05-14 17:54]: > > * Ulrich Leodolter <[email protected]> [2010-05-14 13:09]: > > > On Fri, 2010-05-14 at 10:27 +0200, Wolfram Schlich wrote: > > > > Hi! > > > > > > > > I'm using Bacula 5.0.2 to back up to a tape library > > > > which has two LTO-4 FC tape drives. Backup speed is > > > > around 95-100 MB/s which is quite ok (using a DAS > > > > for spooling data though). > > > > > > > > Now, when running a copy job that copies backups > > > > from a tape from the full or incr backup pool to > > > > a tape from the offsite pool, speed reaches 50MB/s > > > > maximum, so it's just half as fast as the backups. > > > > > > > > What could be the reason for that? > > > > > > copy is NOT done in multi-threaded buffered way. > > > it is done one by one block (default is 63k) > > > > > > ... > > > read block N > > > write block N > > > read block N+1 > > > write block N+1 > > > ... > > > > > > so you get about the half speed. > > > > [...] > > > > > this is why we do a second copy-disk-to-tape > > > using a special sql query to make offsite copies. > > > > Well, the problem for us is that we don't backup > > to disk because the storage isn't big enough for > > that, so we backup to tape using the storage as > > spool device (which is able to spool data for 4 > > LTO4 tapes). > > Dear Kern, dear Bacula developers, > > do you plan to change this part of the implementation > of Bacula to greatly improve the speed of copy jobs > for tape-to-tape copies?
Yes, I am working on this now (a very low priority project for the moment) but it will probably only be in the Enterprise version and not in the community version. Kern ------------------------------------------------------------------------------ ThinkGeek and WIRED's GeekDad team up for the Ultimate GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the lucky parental unit. See the prize list and enter to win: http://p.sf.net/sfu/thinkgeek-promo _______________________________________________ Bacula-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/bacula-devel
