Original question in the bottom of this message
Lots of input from several people (thanks all) on this one. We haven't been
able to test the move, but we are planning to use the export/import
utilities.
>From dr Tom Blinn (compaq):
=======================
I'm not intimately familiar with Informix, but I suspect that if you
want Informix to be able to USE the extra space, you've probably got
to have it move the data -- possibly by an export to some other file
(e.g., a tape) and then an import. I don't understand what you mean
by "file" when it's in a raw partition. By definition, raw disks do
not contain a file system, so there are no files in the usual sense,
just an unformatted bit array (the raw parition itself), and in some
of the partitions, part of the space is normally reserved for use as
a disk label (although you don't HAVE to have a label on a disk if
you only use the whole disk without any partition structure).
If you "dd" the "c" partition (which contains the disk label) from a
smaller disk to a larger disk, you'll move all the data, but you'll
also move the disklabel (you must zero the label on the target disk
or "dd" will not be able to copy the raw partition onto it), and if
you want to use the larger disk's full size, that's not going to do
what you want.
>From Colin Bull
============
dbexport is easiest way. (Beware IDS 7.31 has bug in dbexport command)
>From Mike Mehall:
===============
We used dd to make a backup of raw Informix
partitions on 7.3.1 because that was the first release of Informix to
support dd as a backup method.
>From Hannes Visagie:
==================
Stop, Informix can only see 2 Gig chunks. So you have to slice your 9 gig
drive into 2 gig chunks. Partition a to h.
Now a couple of ways, but easiest is
1. Your Informix links to raw devices must be soft links.
Shutdown DB, oninit - ky
change link from eg.
/usr/informix/data/raw01 -> /dev/rdisk/dsk5d {d is 2 gig raw} to
/usr/informix/data/raw01 -> /dev/rdisk/dsk6a {a is 2 gig slice on new 9 gig
drive}
now dd if=/dev/rdisk/dsk5d of=/dev/rdisk/dsk6a
Startup DB, oninit
2. You can add a mirror chunk to Informix, then break the original chunk
away. Ask NG how to.
Please note that if you did not use soft links, you are in trouble. You
will
have to do a export/import.
Always use soft links to your data
>From Alan (Compaq)
=================
A dd(1) command will just copy blocks. Moving a 2 GB chunk of data to a 9
GB space will just fill up the first 2 GB of the 9 GB space. You should
check the documentation for the database system and see what they recommend.
Odds are, the database software knows how big the database was when it was
created so moving the space around will still just leave you with a 2 GB
database. The database system may support
a method to expand the database to take advantage of more space, or you may
have to export the data and then recreate the database.
ORIGINAL Question:
> Hi managers,
>
> What is the best way to move an informix database from a raw partition
> (file is aprox 800 Megs and disk is 2Gb) to a a new disk of 9 Gb ?
>
> Will a dd copy work with the different disk sizes (assuming I am planning
> to dd from c-partition of smaller source disk to c-partition of larger
> target disk)
>
>
>
Received on Fri Nov 30 2001 - 14:08:34 NZDT