Problem of varyon with a dead disk in mirroring

UNIX AIX
1

Hello,

On a RS6000 server I have two disks (hdisk0 and hdisk1) which are mirrored in a logical volume rootvg.
Yesterday one of these disks failed. Diagnosis, physical death.
It has therefore been replaced by a brand-new.
In terms of parameters, hdisk1 is now N# 1 in bootlist, everything is OK (hd5 is on, bootable ...)

At the first start, the boot sequence is hold, and the front LED display shows error code 0552.
A small turn in the documentation teaches me that this means ipl_varyon is not running ok.

On an equivalent server we try to repeat the config.
If hdisk1 is removed , hdisk0 boots, if hdisk0 who plays the role of dead HD is removed, hdisk1 does not boot.

After a nice series of tests of all kinds, here's what I tell myself ...
Does the hdisk0 (the one dead) may be a flag somewhere that allows a boot even if only 1 of 2 disks of the quorum is present while hdisk1 have this same flag disabled thereby excluding a boot rootvg if 1 of 2 disks is missing.
Yet as part of a mirroring, the discs are equivalent, there is not one that would be "master" more than the other, is it?
The variable MISSINGPV_VARYON is set to TRUE in /etc/environment, I think it would solve the problem but not.
I can not find anything, anywhere (smitty, /etc/environment ...) which proves this.

That tells something to someone ?

2

Hi,
you should have removed the dead disk from the mirror before replacing since the bosboot doesnt work any more if you have any bad disk in rootvg. I was not aware that this problem still exists, I had it several times with AIX 4.x ... What you can try is to boot from an image or cd into maintenance mode and try to unmirror rootvg. If this doesnt work, remove just the (no more existing logical volume copies - there is a forced option that allows you to do that. Do you still have a dumpdevice on the remaining disk? If not create one. Did you have a dumpdevice on the missing disk? If so - remove it.

If this doesnt help, you might need indeed restore from backups ... but I think it's at least worth a try.

Kind regards and good luck,
zxmaus

3

Hi,
Thanks a lot.
We'd got many problems since, but unmirroring, reducing and removing was the solution.
The same thing, in an inverse order, and system is ready.

Thank you again