I thank you all, for your helpful replies.
Not the situation I was hoping for-- but it is what I expected. (Just was hoping that I was insufficiently knowledgeable in Informix admin, and there was some admin capability of which I was unaware, to manage the root dbspace.)
We have two such instances that I want to re-engineer. One has multiple chunks in the root dbspace-- so I can get rid of all but one. The other has only a single chunk. In both cases, I will be left with a >50GB chunk for the essential rootdbs objects.
Doesn't seem "neat and tidy", but I guess we'll just carry around the excess baggage.
Or, I had thought about creating a new instance (with a small root dbspace) from scratch, and using dbimport (actually Art's replacement because of the parallelization that speeds things up quite a bit) to re-establish all the databases. But, then I thought that means losing the current sysadmin database. SInce Scheduler database jobs don't belong to the database, but to sysadmin, that's just something else to worry about and give me grief.
Is there any reason I can't use dbexport/dbimport to move the current sysadmin database to a newly minted instance, into which I import all the old databases (but with a smaller root dbspace?) Exporting and importing
all the databases seems an inelegant and time-consuming way to achieve the desired result, but I'm thinking it would probably work. Would you concur?
There sure are a lot of loose ends in Informix, with regard to admin capabilities. I think it boils down to a philosophical thing. My world is database-centric. Informix's world is instance-centric.
Anyway, I appreciate the comments.
Onward and upward.
Thank you.
David Grove
Alaska Dept. of Corrections
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David Grove
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Original Message:
Sent: Fri May 22, 2020 03:40 PM
From: David Grove
Subject: Decrease Size of Root Dbspace
IDS 12.10.FC12
IDS 14.10.FC3 (upgrading very soon, so if it can be done in 14 that would be great)
Solaris 10 1/13
Consider the following scenario:
Many years ago an experimental Informix instance is created. The Oracle S.A.M.E. (Stripe and Mirror Everything) method is adopted, and everything (I mean everything) remains in the root dbspace (which is distributed over many spindles to spread all I/O evenly across all drives).
Some years later, a DBA comes along and wants to enhance performance of some tables (at expense of others). So, he creates new and separate dbspaces for tables, indexes, sblobs, logical logs, physical logs, and temp spaces. He uses dbexport and dbimport to move all the databases out of the old root dbspace. In fact, he moves everything (except stuff he can't, such as reserved pages) out of the old root dbspace.
Now a root dbspace that once needed 100GB requires almost no space.
IOW, now almost 100GB of space is completely wasted.
So, the DBA thinks, "What a waste", and wants to shrink the root dbspace by about 99%.
How can this be done?
Thank you.
DG
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David Grove
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#Informix