Re: Recovery Question

On Jul 23, 11:32 pm, "fitzjarr..._at_cox.net" <fitzjarr..._at_cox.net> wrote:
> On Jul 23, 8:17 am, Paul <paulwragg2..._at_hotmail.com> wrote:
>
>
>
> > God I love helpful people - do you want me to spend an hour explaining
> > why we can't back up the data or do you just assume that in every
> > single situation you are right and the poster is an idiot? I stated
> > the data is not backed up for a reason, I even said don't bother
> > mentioning it.
> > We do not 'maintain the data' for anybody. We supply software to
> > customers. They maintain their own databases. Every now and again they
> > have a problem, either with the data, or with performance. As some of
> > our customers have very large databases, these are the best databases
> > for us to use for either problem investigation, or for performance
> > tuning. So we use them. They are not backed up as quite frankly we do
> > not give a stuff what happens to this data - we do not need to recover
> > it. Their databases contain confidential data, and part of the
> > agreement is that we have to either anonymise their database prior to
> > them shipping it, or we cannot back it up. Is that clear?
> > Now that I have wasted the time explaining that, back to the original
> > point.
> > The original database was running 10.2.0.2.0, with all data files
> > stored in d:\oracle\oradata\<Instance>. The instance was not running
> > when it died. It is the 32-bit version of WIndows and Oracle.
> > The machine has been rebuilt,but I now need all of the data to be in f:
> > \oracle\oradata\<instance>
> > I cannot just recreate the instance, then overwrite all of the files,
> > because as far as the control files are concerned the data files all
> > live in drive d: When I tried copying the original control files
> > across it gave the error "could not identifiy control file".
>
> > I do actually have an export of the data prior to the point at which
> > the machine died - all that actually happened by the way is that the
> > disk with the Oracle Home on it died completely.
> > I could quite easily recreate the instance and import the data, but I
> > hoped that I could find somebody helpful to allow me to expand my
> > experience.
> > I do not see that this would be a different process whether using 32-
> > bit or 64-bit,and I do not really see what ports have to do with
> > anything either. I realise that people here have vastly greater
> > experience than myself, which is why I was hoping for a bit of help,
> > maybe others would rather just put people trying to learn down rather
> > than coming up with any helpful suggestions.
>
> 32-bit operating systems can access no more than 4 GB of memory,
> period, and as such usually inflict a file size restriction of 2 GB;
> this puts your 7 GB file 'out of the ball park' as far as
> accessibility and 'recognizability' to the software. With 64-bit
> releases the number of available memory addresses increases almost
> exponentially, and with that the availability of single files larger
> than 2 GB.
>
> I can't understand how you
>
> 1) built a datafile larger than 2 GB with this software
> 2) had a database running so you could load data with that
> configuration
>
> Your best bet in this instance is to simply recreate the database,
> with files sized to 2 GB or less, then import your recent export and
> go from there.
>
> David Fitzjarrell

Yikes! So much misunderstanding in one post!

A 32-bit operating system has no problem whatsoever with files bigger than 2GB. It would be odd maths indeed if that was the case, since 2^32 implies a 4GB limit, not a 2GB one!

As it is, on 32-bit Windows using NTFS, you are allowed files up to about 16TB in size. (See, for example, http://www.pcguide.com/ref/hdd/file/ntfs/files_Files.htm and/or http://en.wikipedia.org/wiki/NTFS)

In Oracle itself, you have a problem of not being able to address more than 2^22 database blocks (because that's the number of bits used to store unique block numbers within a file), which means 4 million blocks for a 32 bit installation -which, at 8K per block, would imply an Oracle file size limit of 32GB (the maths changes if you use bigfile tablespaces). Received on Mon Jul 23 2007 - 18:34:39 CDT