From: mfaurot@bogart.uucp (Michael Faurot)
Newsgroups: comp.databases.informix,comp.sys.ibm.pc.rt
Subject: tbtape problems with OnLine & IBM RT
Summary: can't back-up OnLine partitions
Date: 4 Jan 93 13:32:48 GMT
Followup-To: comp.databases.informix
Organization: ism:c:m/xo


Several weeks ago I posted the message you'll find below.  I received one
follow-up post from David Kosenko (davek@informix.com) which provided a
means of being able to get back at the database by changing the value of the
MIRROR parameter in the tbconfig file from 0 to 1.  David further suggested
the problem was likely due to bad blocks on the physical device and a low
level format should be performed to attempt to lock out the bad blocks.

Initially I was of the opinion that bad blocks were not the problem as I was
able to read the entire raw patition via the dd command without any read
errors.  But just to satisfy myself, I went ahead and did the low level on
the device, and the problem still remains.  The device is an external IBM
9332 style 200M SCSI device.  I have partitions all over the drive and have
NEVER had any read errors of any kind with any of the AIX (ie, regular)
partitons.  I've further tried shuffling the OnLine partiton to different
areas on the hard disk and the problem still remains.  I feel very confident
at this point there are no physical problems such as bad blocks on this disk
drive which would cause OnLine to barf.

At this point in time I find OnLine to be utterly worthless to me.  If I
can't back-up my data then the product is useless to me.

Is this a known bug in this release/port of OnLine?  Is there a fix or
update for it?


Here follows the text of my original post and problem:

==============================================================================

Have the following hardware, OS, and Informix . . .

	IBM RT 
	AIX 2.2.1
	Informix OnLine v4.00.UD4

Here's the problem . . .

	After initializing rootdbs and shared memory without any
	difficulties I use ISQL to create a couple of databases, fill
	one of them up with records and the other is simply empty.

	Now I wish to back-up this entire configuration to tape.  So I
	use the Archive option from within tbmonitor.  I then choose
	the option to Create, mount the tape in the drive, select "0"
	for a level 0 archive and then receive the following error
	message:

		Error reading from the disk, Error No. = 5.

	If I don't shutdown OnLine, I can still access the databases
	but if I do shutdown OnLine, I get the following error messages
	when I attempt to bring it back up:

		Bad Primary Chunk '/dev/rootdbs'
		tbinit: fatal error in shared memory initialization

	I'm fairly certain there's nothing wrong with the tape
	perameters I'm using because, oddly enough, if I only create
	the first database, I can back-up the system without it
	corrupting the rootdbs.  It's only after I add the second
	database and attempt to back it up that it trashes rootdbs.

	If I make no attempts to back-up the OnLine partitions, OnLine
	goes up and down just fine.  

Has anyone run into this before?  Know a fix?  Could this be related
to improper setting for shared memory and semaphores?  If related to
shared memory etc., could someone please email me either their
/etc/master file or the relavent stanzas from it?

Thanks.
-- 

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Newsgroups: comp.databases.informix