Kern Sibbald wrote: > Hello, > > I haven't seen the original messages, so I am not sure if I understand the > full concept here so my remarks may not be pertinent.
Personally I wasn't suggesting a format change - I'm pretty happy with the fake-tape volumes for on-disk storage (though I wish bextract and bls didn't need a configured sd to read them). My own suggestion (which started this thread) boils down to "getting decent concurrent writes to disk with a bacula-sd currently needs (IMO) too much configuration of -sd and -dir and too much fiddling around. Should a disk-aware sd provide a mechanism to open the same device multiple times with DIFFERENT mounted volumes, auto-create disk devices on demand, or otherwise provide an easier config-free way to concurrently write to multiple volumes?". If I wanted to propose another on-disk format, which I don't, I'd propose zip64 with all metadata, checksum info etc not supported directly by that format embedded in a custom-format .bacula file inside the archive. That way backups could be extracted by something other than bacula in a disaster recovery situation. As it is, though, I'm pretty happy with the format, it's the way bacula-sd acts as a gateway to disk storage that I think needs improvement. BTW, When I suggested that greater write concurrency would be desirable and should be easier, Phil Stracchino raised some concerns about concurrent writes to a file system increasing fragmentation and hurting overall performance. Rather than just wave my hands about that I've put together a testing tool for concurrently writing big files from multiple threads that optionally uses posix_fallocate to pre-allocate ahead in chunks up to total file size. It tracks per-thread and total runtime and time spent in write() and posix_fallocate() calls. I'm doing some tests with it now and will post it to the bacula-devel list too. I'm planning on testing the real effects of various levels of concurrent writes on common file systems with it using a controlling shell script and will report back when that eventually finishes. -- Craig Ringer ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
