Multiple Residency & Shared Memory

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? Thanks, Ted Slusser Sent via Deja.com http://www.deja.com/ Before you buy.

your two instances won't share the same memory space,or segments. after you bring your second instance up you can see which 'keys' belong to the memory segments : ipcs -a | grep informix will show which memory your os has allocated for each instance. too many segments listed will indicate you need to reconfigure the total first segment size, and possibly the additional segments if needed. Probably the main consideration is how much mem your box has in toto, and how much it needs for other applications and overhead . 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? > > Thanks, > Ted Slusser > > Sent via Deja.com http://www.deja.com/ > Before you buy.

Your servernum onconfig param will determine second instances shm address. (onstat -c|grep SERVERNUM) Even if you're using a multiple residency or make another installation on same box pick a different number. Since it's a unique number formula goes like.. shm_addr = (servernum * 0x10000) + 0x52564801 Verify with ipcs command on your current installation. Alkin TEZUYSAL INFORMIX DBA 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? > > Thanks, > Ted Slusser > > Sent via Deja.com http://www.deja.com/ > Before you buy.

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 (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

Thanks! I believe I have it working now. In article <39339DD0.43D97E2@home.com>, Edward Rosenthal <edrosenthal@home.com> wrote: > your two instances won't share the same memory space,or segments. > after you bring your second instance up you can see which 'keys' > belong to the memory segments : ipcs -a | grep informix > will show which memory your os has allocated for each instance. > too many segments listed will indicate you need to reconfigure the > total first segment size, and possibly the additional segments if needed. > Probably the main consideration is how much mem your box has in toto, > and how much it needs for other applications and overhead . > > tslusser@bigfoot.com wrote: > Sent via Deja.com http://www.deja.com/ Before you buy.