I'll have to look at the amanda-devices page for the exceptions. But I can tell you that while amanda is skipping some level 1 dumps on me, because of calculated size, and I am using vtapes. Amanda is telling me that its filled the tape and then keeping things in the holding area.
I suspect that in the case of vtapes, amanda will finish writing the current DLE even if it crosses the size boundry, but that it will not write additional DLEs to tape above the set tape size limit. hum, not seeing what I'm looking for. My vtapes do fill though. On Fri, Oct 25, 2013 at 08:50:28AM -0500, John G. Heim wrote: > > Last week I asked a few questions about virtual tape size. Well, I > wouldn't say I resolved them but I think I have one clue. One of the > things I asked about is the meaning of the "length" parameter for a tape > definition. I had set it to 25G for my virtual tapes but amanda was > writing 38G to each vtape. This was going to be a problem because I > have a quota on my virtual tape file system of 2Tb and I had therefore > calculated that I could create 80 25Gb tapes. Here is what the > amanda.conf man page has to say about the tape length parameter: > > > length int > > Default: 2000 kbytes. How much data will fit on a tape, expressed in > > kbytes. Note that this value is only used by Amanda to schedule which > > backupswill be run. Once the backups start, Amanda will continue to > > write to a tape until it gets an error, regardless of what value is > > entered for length (but see amanda-devices(7) for exceptions). > > The device for virtual tapes is vfs-disk or something like that. But I > couldn't find anything in the docs for how it determines how much to > write to a vtape. If it keeps writing until it got an error, in my case, > it would write over 2Tb until it hit the hard quota on the filesystem. > So that couldn't be. > > Then it occured to me that 25 * 150% = 38G. . Coincidence? I recreated > the vtapes with a size of 16Gb. Now amanda is writing 25Gb to each > tape. My first backup wrote to 11 tapes. Slots 1-10 have 25Gb on them > with 19G on the last. The amount of stuff on tapes 1-10 is not exactly > the same on each tape but it's a little over 24G each. > > IMO, this borders on a bug. The wiki strongly implies that you can take > your disk file system size and divide by the number of tapes to get the > tape size. While the amanda developers aren't responsibe for the wiki > being misleading, it is natural to assume the length parameter for a > virtual tape is the actual size of the tape. I'm not the only one who > made that assumption, so did whoever wrote the wiki entry on virtual tapes. > > Anyway, I'd still like to know how amanda determines when to stop > writing to a vtape. I can put comments in my amanda.conf to say that the > tape length is set to 16G so amanda writes 24G to 25G to each tape. But > that's hardly an ideal solution. > > > > -- > --- > John G. Heim, 608-263-4189, jh...@math.wisc.edu --- Brian R Cuttler brian.cutt...@wadsworth.org Computer Systems Support (v) 518 486-1697 Wadsworth Center (f) 518 473-6384 NYS Department of Health Help Desk 518 473-0773
