Very Computer

We are running AIX 4.3.3 and Informix Dynamic Server Version 7.31.UC3. I am
wondering if Informix writes any information over the AIX logical volume
control block (LVCB) at the first 512 bytes of each logical volume. When I run
the command "onstat -pP 1 0" I see the following:
******************************************************************
carsi: oncheck -pP 1 0                                                    
addr     stamp        nslots    flag type                 frptr frcnt next    
prev      
100000   1273408739 1      1000   ROOTRSV      124   3964  0        0      
        slot ptr   len   flg                                              
        1    24    108   0                                                
slot   1:                                                                
    0: 49 4e 46 4f 52 4d 49 58 2d 4f 6e 4c 69 6e 65 20     INFORMIX-OnLine  
   16: 43 6f 70 79 72 69 67 68 74 28 43 29 20 31 39 38   Copyright(C) 198
   32: 36 2c 20 31 39 38 37 20 20 49 6e 66 6f 72 6d 69   6, 1987  Informi
   48: 78 20 53 6f 66 74 77 61 72 65 2c 20 49 6e 63 2e   x Software, Inc.
   64:  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0            
................
   80:  0  0  0  0 10  0  0  0 33 ba 5a a4  0  0  0  6          
........3:Z$....
   96:  0  0  0  0  0  0  0  0 37 2e 33 30                          
........7.30....
**************************************************************************
**********
This looks to me like at least some of the LVCB was overwritten by Informix, if
this slot exists at the beginning of the logical volume. I am coming from a
Unix admin perspective and don't know much (yet) about Informix so appreciate
any info. Thanks. CKG

If you are using AIX's logical volumn manager, I think that you need to use an
offset
for the start of the chunk. It's been a while since I've looked at this, but I
think that
on AIX if you do not do this, then the first set of pages will be overwritten by
AIX
when the system is next booted.

Hi,

Honda75:
Yes, you are right, Informix overwrites the LVCB if you do not specify an offset for
your chunk/dbspace. Therefor it is good usage to specify an offset of 1 page (4k).

Madison Pruet:

No, AIX does *not* overwrite the "destroyed" LVCB during reboot. AIX checks for a
valid LVCB, if its overwritten it does not recreate it. The only consequence is that
some LV-Informations are lost and cannot be used by LVM.

Regards
--
Helmut Leininger

Bull AG / Vienna
Open Systems Support

This opinion is mine and not necessarily that of my employer.
No guarantees whatsoever.