On 03/29/10 06:53 PM, Kern Sibbald wrote: > On Monday 29 March 2010 18:01:56 Henrik Johansen wrote: >> On 03/29/10 05:08 PM, Kern Sibbald wrote: >>> On Monday 29 March 2010 16:59:05 Phil Stracchino wrote: >>>> On 03/29/10 08:22, Henrik Johansen wrote: >>>>> We'll top 300+ devices per SD once we are finished migrating. >>>> >>>> I hope you'll post a full writeup somewhere. :) >>> >>> Oh, I hope not. I am believe that anything more than about 10 devices is >>> the wrong way to configure Bacula, and with 300+ there is very little >>> chance that it will work. >> >> Would you care to explain why this will not work with Bacula ? > > Assuming you are writing to all of them, or a large number at the same time, > there are a number of possible problems:
I would most likely write to 100 volumes per SD (300 volumes in total on 3 machines) simultaneously. > > - you may severely fragment your harddisk. Not a problem in our case. > - you will have 300 open file descriptors, which is too many on most systems > especially Solaris systems. Not a problem : A 32-bit program using standard I/O is limited to 256 file descriptors. A 64-bit program using standard I/O can use up to 2 billion descriptors. The limit for 32 bit apps is easily tunable. > - you will have 300 device descriptors open in Bacula, which could consume a > substantial amount of memory, overhead, and lock usage. I'll do some profiling (thank god for dtrace) to see whether or not this is a problem. Memory is not a problem since the max on the type of system we are using is 256 GB. > - depending on what sort of Pools you have defined, you may start running into > practical limits for Bacula for the number of simultaneous volumes you are > using -- anything more than about 20 would concern me. > - pruning and Volume management within Bacula may become more difficult due to > the large number of Volumes involved. This indeed needs a bit of research. > - you may be starting and stopping the SD often to do device management. This > could disrupt operations, and we are not planning to add code to the SD to > reload its conf file while running. I already scriptet my way out of this one ;-) > The sum of the above *may* not be important. However, any one of them *could* > be a real "killer". If you are only running a small number of concurrent > jobs, some of the things I mention above may have a much smaller impact than > I am imagining. > > Best regards, > > Kern -- Med venlig hilsen / Best Regards Henrik Johansen hen...@scannet.dk Tlf. 75 53 35 00 ScanNet Group A/S ScanNet ------------------------------------------------------------------------------ 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-devel mailing list Bacula-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-devel
