Jon LaBadie wrote:
On Tue, Apr 26, 2005 at 09:49:12AM -0400, Kuas wrote:Thanks for the reply, sorry for the stupid kind of question. I'm really new trying to configure it.
I didn't have autoflush turn on before (in amanda.conf), I thought amanda will flush the content of the holding disk to the tape(=slot, since I am using file-driver). Is this right? Then I found a problem with amdump, in the log said that it does not have holding disk anymore. How big is the holding disk supposed to be? Equal to the size of each tape? I left it default: use 290 Mb and chunksize 1GB, while my tape size is 4GB for now.
Think about traditional tapes, not your vtapes. Only one thing can be writing to the tape drive at a time. But ...
I may have 50 clients, each with multiple DLE's. Do I really want to dump 1 DLE at a time through hundreds of DLE's? Probably not, so I want to be dumping 2, 5, 10, 25 DLE's all at the same time, but only one thing can be writing to the tape at a time. The holding disk is used to collect those DLE dumps while they are in progress and the completed dump until it can be transfered to tape (the one thing writing to tape remember).
If you use no holding disk, or the available space in the holding disk is too small, then that DLE is written directly to tape, i.e. the one thing writing to the tape is a dump in progress, not the transfer of a completed dump.
Your holding disk is probably doing you no good at all. Unless you have several DLE's substantially less than 292MB (maybe incre- mentals). And the pair, 292MB with allowed "chunks" of 1GB is kind of silly. Tough to fit a 1"G"B chunk on a 292"M"B disk. Also, if you used defaults, the "reserve" is 100 meaning 100% of the holding disk can not be used for level 0 dumps, only incremental.
If your a small installation and don't mind doing one DLE at a time, eliminate your holding disk. Otherwise make it larger and more useful. I've currently got 3 holding disk pieces, totaling about 120GB. For a 9GB nightly run, that gives me lots of space to hold dumps if I forget to change tapes. Or it is broken as it is now.
Reading back the manual about holding disk, it's kinda strange the holding disk area is smaller than a one-chunk size. I think it should be the other way around or at least equal. And the value should be as big at least the size of the tape.
Back to the VTape concept, since the VTape is on the same disk as the holding disk. I don't see any reason why it has to store it temporarily first to the holdingdisk area? Can anybody see the drawback to turn holding-disk off (set to "0") and write all the dumps from the client straight to the vtape right away and having the parameter "inparallel=4" so that it will be able to service 4 dump at the same time? The previous case, after writing to the holding disk, it will have to schedule the flush.
Thanks in advance for any comments.
Kur.
