On Monday 18 November 2019 02:11:07 Charles Curley wrote: > On Mon, 18 Nov 2019 13:13:00 +0700 > > Olivier <[email protected]> wrote: > > I am wondering what is the best size to declare for the lenght of > > the vtapes. Too long a vtape could lead to disk space being unused, > > You may have a misconception here. Vtapes emulate physical tapes, but > not in all respects. If you don't fill up a tape, that unused space is > gone. But if you don't fill up a vtape, it simply means there is that > much space available for other files, such as other vtapes. > > So in theory you could allocate more vtape space that there is room on > the partition. Just make sure you never use more vtape space than you > actually have. > Track that usage with an occasional df. And I'm glad you asked as I see I am about to have a problem. Using a 2T drive with 60 vtapes on it, I am very close to full. As in I've never been this close before.
/dev/sdd1 1921802432 1802889848 21220528 99% /amandatapes So I need to add 2 days to the cycle, making the average backup a little smaller. Done. So far, amanda has not given me any media full warnings. Trouble till now has been avoided because one of the 5 machines being backed up here has been changed out, and the new one has not been re-added to the schedule. So I'll look in 2 or 3 weeks or so to see if theres room for that 5th machine. Its an rpi4, but it has around 400 GB of SSD's attached too. Otherwise it may be time to go get a 4TB drive. > > but > > having too many small vtapes one or two directories created for each > > new vtape, and if many vtapes, the main directory containing them > > would not fit in a single inode; but the space left unused would be > > smaller. > > > > My understanding is that splitting a backup does not consume more > > space, so it is not the backup data that gets bigger, only what is > > surrounding it. > > > > If wee are not considering the overhead of computing the tape > > spliting, nor the possible extra I/O, if we only focus on the disk > > space, what would be the optimum size for the vtapes? > > The answer to that is, "that depends". I have tried to have a vtape > size a bit larger than my typical daily backup, and then allow amanda > to use enough extra tapes to cover the largest likely backup. So most > days I use one vtape, 40-90% filled. Some days I use three or four > vtapes. All but the last are almost 100% filled. You can also play > with your split size. > > I suggest you do the rough calculations to get your initial setup, > then fiddle with it as you gain experience and as amanda settles its > calculations down over time. And adding 2 days to the cycle might not be enough, but I am not going to further disturb amanda until I have recovered from a aortic heart valve replacement in mid December. I don't recommend gettong old, its a PITA. But its also fun since the reaper has come for me twice now, and blinked both times. :) Copyright 2019 by Maurice E. Heskett Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
