Hi, * Jon LaBadie <j...@jgcomp.com> [20180409 17:34]: > On Mon, Apr 09, 2018 at 01:20:05PM -0400, Jean-Francois Malouin wrote: > > Hi, > > > > It's with some shame that I must admit that through the long years of using > > amanda I've never really played with the bump* parameters for DLEs! > > > > I'm now in a situation that might benefit from some tuning using those > > to aggressively encourage bumping the gnutar incremental levels. The > > drawback of potentially needing more tapes for recovery is not really a > > constraint for me. > > > > I have a DLE (~5TB) for which the estimates are done on the server -- > > the client, a NAS/filer, doesn't support anything else, so the DLE usage > > info is really just from the historical usage not the current one. Any > > ideas/hints on how should I proceed from what is currently (default > > values I guess) configured? > > > > bumppercent 20 > > bumpsize 20480K > > bumpdays 1 > > bumpmult 4.00000 > > > > Would setting bumpdays to higher values (2 or 3 days) pull in the > > direction I want to go? > > > > Since bumppercent != 0, bumpsize is ignored from the man page, so I > > guess the only important parameter left is bumppercent. Should I > > increase it or decrease it? I'm having a hard time understanding what > > the doc says for amanda.conf says... > > As you note, your bumpsize is ignored. > > The bumpdays parameter gives the minimum number > of dumps at each level that must be done before > the next higher level is even considered. > > bumpdays is often recommended to be set to > 1. > The rationale being that if you have two level 1 > dumps, one could be lost without much concern. > But if you only have a single level 1, losing it > could be a big problem. > > I question your multiplier in "bumpmult 4.0". > It says to go from level 1 to level 2 the level 2 > needs to be 20% smaller than the level 1. But > to go to level 3, the size of the expected level 3 > dump must be 80% (4.0 x 20%) smaller than the > expected size of a level 2. And it will be really > hard to get to level 4 as it must be 320% smaller > than the expected level 3 (4.0 x 80%). > > I'd suggest picking a bumpdays with which you are > comfortable, get that multiplier down (1.0? 1.2?), > comment out bumpsize, then see if 20% gives you > what you want, if not start adjusting it. > > BTW, if you make a specific dumptype for that > DLE, you can play with the bump settings in that > one dumptype definition without affecting other > DLEs. They would be using the global values.
Thank you for the explanations. I will start experimenting with: bumppercent 20 bumpdays 2 bumpmult 1.2 and what it leads to. Kind regards, jf > > Jon > -- > Jon H. LaBadie j...@jgcomp.com > 11226 South Shore Rd. (703) 787-0688 (H) > Reston, VA 20190 (703) 935-6720 (C)