On 04/ 2/10 01:13 PM, Kern Sibbald wrote: > Hello, > > Over the past several weeks James and I have been discussing a rather sticky > point with doing System State backup and restores via a Bacula plugin. > > The basic problem works down to the fact that we do the backup, we first have > the names of the files to backup, which we do, then we get some special > writer XML data to save. This is no problem. > > However, on the restore, to properly restore to writers, we must first present > the XML data, then we can write the file data. This is a real problem > because Bacula puts data sequentially on a Volume (tape or disk) and then > restores it sequently. There is no mechanism in Bacula to write some data > after backing up files, then get that data *before* restoring the files. > > For a typical system state backup, this XML metadata represents something like > the following in bytes: > > 2604 > 463820 > 754 > 3378 > 1610 > 4636 > 1414 > > there are a number of meta data files, because the system state backup > consists of backing a number of different "components" > > Now, we could compress this data, and store it in the catalog, but that is a > bit "ugly" and requires transmitting it back to the FD in some way during a > restore. Compressing the data reduces it to about 20-30KB rather then the > 500KB. > > Another idea is to spool the file data in either the File daemon or Storage > daemon, until we receive and write the meta data to the Volume, and then > despool the file data -- thus during a restore the xml meta data would be > restored (given to the plugin) first. > > On James' system the file data backed up during s systems state is about 200MB > (not a lot to spool). However, he believes that he has seen something like > 1GB of data produced by ntbackup, so that would be a lot more data to spool.
The average W2K8 System State backup hovers around 11 GB - some of our servers produce 20+ GB per System State backup. > One of the problems of spooling, is that if it fails, it will be relatively > serious, because in order to get the meta data, we need to tell VSS that the > backup of the files was complete, which changes the state of VSS (i.e. if you > are doing an incremental backup of the system log files, you cannot just > repeat the operation). > > Does anyone have any ideas or suggestions preferences? > > Best regards, > > Kern > > > > > ------------------------------------------------------------------------------ > 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 > [email protected] > https://lists.sourceforge.net/lists/listinfo/bacula-devel -- Med venlig hilsen / Best Regards Henrik Johansen [email protected] 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 [email protected] https://lists.sourceforge.net/lists/listinfo/bacula-devel
