Re: Multiple Residency & Shared Memory
----- Original Message -----
From: "Art S. Kagel" <kagel@bloomberg.net>
To: <informix-list@iiug.org>
Sent: Wednesday, 31 May, 2000 03:45 AM
Subject: Re: Multiple Residency & Shared Memory
> tslusser@bigfoot.com wrote:
> >
> > Hi,
> > I want to initiate a second instance of Informix OnLine server 7.23.UC1
> > on Solaris 2.6. My question is "Do I need to set a different shared
> > memory base address or can both instances use the same shared memory
> > segments?" How would I calculate the shared memory base address for
> > the second instance if it is necessary?
>
> No, the shared memory base address is just the address at which the
engine's
> executables will attach shared memory when they attach to it. It is an
> internal address and is platform dependent. Leave that value the same in
> both ONCONFIG files. The value that has to differ for each instance is
the
> SERVERNUM parameter in the ONCONFIG file. It is added to a base key
number
> to generate a unique, per instance, shared memory key. The base key is
> 0x52564800 to which is added 0x10000 * SERVERNUM plus the segment number
^^^^^^^^
FYI, the base key (shmkey in Administrator Guide) is 52564801 (in hex) /
1,381,386,241 (in dec)
key value = (SERVERNUM * 65536) + 1,381,386,241 (in decimal) or
= (SERVERNUM * 10000) + 52,564,801 (in hex)
> (ie the first or RESIDENT segment for SERVERNUM=1 will have a key of
> 0x52574801 while the first VIRTUAL segment for SERVERNUM=16 will have a
key
> of 0x52664802, etc.). Just translate the key column in the onstat -g seg
> report to hex to see this effect.
>
> Art S. Kagel
>