Re: Database files on optical disks

andrew_at_cm.co.za wrote:
: Greetings,
 

: Has anyone had any experience of storing oracle data files on optical
: disks. Our situation is this:
 

: we would like to store around 10Gb per year of scanned images and be able
: to access them through our Oracle DB. We are putting in a magneto-optical
: jukebox (40Gb) for bulk storage. The jukebox is driven by VLFS software,
: which migrates files from magnetic to rewritabe optical disks on demand
: transperantly to the user. As I understand the technology (which may not
: be entirely correct!) Oracle opens all its datafiles when the database starts
: up. If they are on the optical disks, the OS will first copy the file onto
: magnetic. To do this it must make space by moving files off megnetic onto
: another optical disk. Oracle can then open the file. Oracle then tries to
: open the next file, which is on optical disk. First the OS moves the previous
: file back to optical to create space, then loads the required file onto
: magnetic, and oracle can open it... This process continues until 5 or 6
: hours later all the 40Gb of datafiles have been opened. Moments later,
: someone forces a checkpoint, and 40 Gb of data needs to be read and written
: again. (another 5-6 hours).
 

: Am I totally on the wrong track, or is the sort of problem I will run
: into.
 

: Our other option is to store the images in binary files on disk and just
: have indexing of file names stored in the database. (This is the method
: we are using currently, but may like to change.
 

: Any ideas would be helpful.

from a sequence of events standpoint, the above is pretty much correct, but i believe Oracle will probably time out if it cannot access a particular datafile after a pre-determined amount of time which is probably going to be much shorter that the juke box can on average place a file on-line. Once Oracle times out on a datafile, it will almost always crash.

i would look into using read-only tablespaces...you avoid the write timeout issues.

jc Received on Mon Sep 25 1995 - 00:00:00 CET