At Mon, 14 Oct 2013 10:20:16 -0500 "John G. Heim" <[email protected]> wrote:
> > I am trying to replace a physical tape changer with a virtual tape > changer on NFS mounted hard disk. I started with the virtual tape > configuration on the amanda wiki at > http://wiki.zmanda.com/index.php/How_To:Set_Up_Virtual_Tapes. > > The example tapetype definition on the wiki has a tape size of just 3Gb. > But the real tapes I'm using have a capacity of 100Gb uncompressed and > 500Gb compressed. That is such a huge disparity that I am uncertain as > to how to proceed. How 'full' are the tapes you have been using, on average? How many tapes has Amanda been using daily, on average? Peak? Just because your physical tapes have an arbitriarly large capacity (and the compressed capacity is very data dependent and is meaningless if Amanda is writing compressed dumps to the tape) does not mean that Amanda is actually using the whole tape (or even needs to). > > I have a quota of 2Tb on the remote file system. My data is about 1.2Tb > total. I want to keep about 2 weeks of incremental data and and I get > about 20Gb of changes daily. So I think the 2Tb quota is about right but > I am uncertain as to how to define the tapes. If your *average* daily dump is 20Gb, then your tape size should be about 20Gb (or maybe a little larger), and you will use 1 'tape' a day (on average). When Amanda does a 'full', you will need more 'tapes' (eg your peak usage -- set numtapes to allow for that). > > I googled for questions about amanda virtual tape size and I saw a > message from someone who set it at over 100Gb. Someone else responded > that it was kind of large but it should work. So I tried setting mine at > 80. and configured 25 virtual tapes. That's 20Tb of space. But inspite > of going 10x over my quota, I've run out of tapes. You have to understand: Amanda will only put one day's worth of backups on a given tape. When amdump starts, it will *always* use fresh tapes. There is little point in making the tapes larger than the size of one day's backup. With your daily incrementals being about 20Gb, a tape size much larger than 20Gb is useless. You might be better off with *smaller* tapes and more of them. > > I'm guessing that 80Gb is too small. But it seems odd that the example > on the wiki would define a tape size of 3Gb. 300Gb seems more realistic > unless I am missing something. You are missing. 80Gb is probably too *large*. > > > > > -- Robert Heller -- 978-544-6933 / [email protected] Deepwoods Software -- http://www.deepsoft.com/ () ascii ribbon campaign -- against html e-mail /\ www.asciiribbon.org -- against proprietary attachments
