Sorry for double-posting. My son just decided to find the shortcut to send a posting while I was still typing. :)
On Sunday 27 November 2005 01:43, Harry Putnam wrote: > One thing I'd like to try is running a specific backup setup on > request that backs up a specific directory every minute. Should be possible. Set up a "file set" that contains this directory. Create a "schedule" that means 'every minute'. And create a "job" that combines the two. > Its not really clear to me yet what happens to different versions of > files in bacula, are the backups generally a mirror of what is on the > file system or can on go back thru different versions like with > rsnapshot? Basically everytime you run a backup job Bacula will create a copy of every file on the disk (at least those you configured in the "file set") to your backup medium (be it a streamer, a DVD writer or another hard disk). Since the backed up data is stored in different "volumes" every backed up file goes to a new volume. So Bacula allows you not only to restore the last version of a file but you can get the file from every version when you backed it up. It may happen that you accidentally overwrote an important document two weeks ago. But the last backup is from yesterday. If you just copied the file you had lost the original document because you backed up the already broken version. With a backup system like Bacula you can restore every version you ever backed up. You can tell it: "Restore the file /home/hputnam/safeguard/tutorials/intro.sxw before the date of Oct 1st 2005." (Of course that's only theory. You don't have infinite space on your volumes and need to throw away (expire) old volumes after a while. In my case I keep backups for two months and then expire the volumes.) There are differences in the kind of backup: Full Backup: You create another copy of all the files every time. This sounds easy but takes a lot of space since you copy everything. (If your backup job is 100 GB and you create a full backup every day then your backup system needs to store 3 TB.) To restore files you just need to look at the last full backup to get your files back. Differential Backup: Let's say you do a full backup once a month but also a differential backup every day. That means that once a month everything is put into the backup. And every other day the system backs up all the changes since the last full backup. This is already a bit better but if you change a large file one day after the full backup you will need to backup it every other day, too. The differential backup makes a copy of all the "differences" (changes) since the last full backup. To restore files you need the last full backup and the last differential backup. Still uses up a lot of space but needs less volumes. Incremental Backup: This is similar to the differential backup. But it just makes a backup of files since any last backup (not just the last full backup). This way you waste as little space on the volumes as possible. To restore files you need the last full backup and all the incremental backups. I don't like to use too many incremental backups because it takes much longer to insert all the volumes since the last full backup. And imagine that you do a full backup once a month and incremental backups every day. In the worst case you need to insert the full backup volume and 30 incremental volumes. This will get you mad if you have a slow streamer. :) A good compromise may be to run a full backup on weekends and incremental backups every other day. > Also I'm wondering if it is best to let bacula write to one volume (in > my case `file') for all the stuff on one client, of if it makes sense > to write to different volumes. All the volumes belong into pools - or even just one pool. Unless you have a good reason you will just create a single pool and let Bacula auto-create volumes in it. I recommend you set "Maximum Volume Jobs = 1" in your pool so that every job goes to a new tape. This is useful so that the "volume files" don't grow too large. Smaller files mean faster restore jobs. If your backup jobs backup a lot of data (>= 10 GB) then you may want to limit the size of the volumes, too. More volumes don't mean wasting anything if you deal with the 'file' type backup. Regards Christoph -- ~ ~ ".signature" [Modified] 1 line --100%-- 1,48 All ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
