Re: Question on the Archive TAPEDEV size

I have the tape size set to 4000000 which means 4 Gigabyte. That works fine. It's claimed here in c.d.i. from time to time that the max size of the tape drive is 2 GB. That is wrong. What do you think all the people with DLT or other large tape drives do? See further comments below: Tom Grenier <tomg@biztravel.com> wrote: :Hi Suj, :I'm not sure if I understand you question correctly, but INFORMIX will :only recognize up to a 2 Gig tape size. We had our onconfig size set to :4 Gig (what our tapes will handle using compression). When I went :beyond 2 Gig the tape just stopped -- no prompt to enter new tape -- :nothing. Only changing the onconfig parameter worked. : :I have the exact number Informix gave me at the office -- if you want it :let me know (it is a little greater than 2000000K). I know of no :problem stating a larger number than the capacity in the onconfig file :-- but if you go over the 2 Gig mark (in onconfig) and you really feed :more than 2 Gig to a tape you are in trouble. : :sujata_soman_at_omm-la2-infotech-001@internet.omm.com wrote: :> :> Hi everybody, :> I have a unique problem. I am being forced to increase the size of my :> TAPESIZE variable in the onconfig file to something greater than the actual :> capacity of the TAPE, if I need my regular backup ( ontape -s ) to work fine. :> Well, this restriction is being forced by some @#$@$ system administration tool :> that is installed on top of UNIX. ( Don't look at me, the decision was not mine :> to take, and besides, I was not here ). Anyway, this tool was working fine until :> version 7.13, and last weekend we upgraded to 7.23, and we don't have a backup :> since then! Does this tool then switch tape automatically when one is full? If it can manage that in a way that is compatible with ontape you do in fact have a "logical" tape drive of larger capacity than your fysical drive. In this case it should work fine to set the tapesize to anything. The fact that it doesn't work any more may be due to some change in how ontape work that your tool doesn't handle properly. :> According to their support staff, we have to disable Informix from :> detecting the end of tape, and let the tool do it. Well, ontape doesn't detect the end of tape. That is the problem with ontape in this respect. (Informix claims there are problems with detecting end of tape on some platforms. I suspect this to be a very old problem that is now resolved on any reasonable platform, so they should realy change ontape to work accordingly.) You in effect have to tell ontape via the TAPESIZE parameter how much data the tape is guaranteed to take BEFORE end of tape is reached. When this much data is written ontape will simply ask for another tape whether the current one is full or not. If ontape ever reaches the end of the tape it will crash and you will have no backup. The only thing I can understand such a tool could do is to be some kind of device driver for the tape that would detect the end of tape, but then not report it back but instead switch automatically to another tape either on another drive or via an autochanger. I think the BMP tools (formerly ztools) are doing something like this. :> The question I have is as follows:- :> Somewhere deep in this user group mail, I remember reading that if you :> actually set the tapesize to more than the capacity of the tape, it might crash :> the server. :> My environment is IBM AIX 4.1.4, Informix ODS ver 7.123 UC1,and for anyone who :> wants the name of the #$@#$ system administration tool, e-mail me !! :> Anybody know anything about this ?? Will it cause serious problems if I do :> this? :> :> ******************************************************************************** :> ****************************** :> * Sujata Soman :> * :> * E-Mail: ssoman@omm.com :> * :> * Database Administrator ( Informix ) :> * :> * O'Melveny & Myers, Los Angeles :> * :> ******************************************************************************** :> ****************************** : :-- :Tom Grenier ########################################################### :# Home: Office: # :# BizTravel.com # :# The Internet company for frequent # :# business travelers(sm.) # :# Phone: (800) 497-1969 (617) 621-3919 x115 # :# e-mail: tom@sqlman.com tomg@biztravel.com # :# web page: http://www.sqlman.com http://www.biztravel.com # :######################################################################## Nils.Myklebust@idg.no NM Data AS, P.O.Box 9090 Gronland, N-0133 Oslo, Norway My opinions are those of my company The Informix FAQ is at http://www.iiug.org