DB2 v9.5.0.4
AIX 5.3.0.0

In our development server we have around 10 instances with INSTANCE_MEMORY set to AUTOMATIC.
There are database ranging 2 - 4 in each of the instances.
Now I have to create two more databases and getting the below error when I try to connect 4th database in the same instance.

FUNCTION: DB2 UDB, base sys utilities, sqeLocalDatabase::FirstConnect, probe:100
MESSAGE : ZRC=0x850F0005=-2062614523=SQLO_NOSEG
"No Storage Available for allocation"
DIA8305C Memory allocation failure occurred.
DATA #1 : String, 299 bytes
Failed to allocate the desired database shared memory set.
The configured DATABASE_MEMORY plus desired overflow may have
exceeded INSTANCE_MEMORY or the maximum shared memory on the system.
Attempting to start up with a smaller overflow allowance.
Desired database shared memory set size is (bytes):
DATA #2 : unsigned integer, 8 bytes
2236088320

All the databases were AUTO configured and bufferpools are also set to automatic.

Any clue is greatly appreciated.

Thanks in advance.

What is your question?

in addition to n_i's question, is it 32- or 64- bit installation ?

It is 64 bit.

The issue is, in any instance when I try to active 4th database, getting the below error.

FUNCTION: DB2 UDB, base sys utilities, sqeLocalDatabase::FirstConnect, probe:100
MESSAGE : ZRC=0x850F0005=-2062614523=SQLO_NOSEG
"No Storage Available for allocation"
DIA8305C Memory allocation failure occurred.
DATA #1 : String, 299 bytes
Failed to allocate the desired database shared memory set.
The configured DATABASE_MEMORY plus desired overflow may have
exceeded INSTANCE_MEMORY or the maximum shared memory on the system.
Attempting to start up with a smaller overflow allowance.
Desired database shared memory set size is (bytes):
DATA #2 : unsigned integer, 8 bytes
2236088320

How can I make sure the memory calculations.

If you set database memory to automatic, I suggest you set each instance memory to approximately 1/10th of the memory available for DB2 (if all of them are active at the same time). However, I have a feeling that, at least for some databases, the database_memory parameter is not automatic.

development server? Then I can give this advice: search for the biggest bufferpool in 1 of the running databases, manually decrease the size considerable, re-try to start the extra database. Because you've just released a fair amount of memory it should work now.
When all the databases are running with STMM enabled (also for the bufferpool you just robbed) things will level out.

P.S. find the developers and compensate them with a cup of coffee.

Thank you for the responses.
Would anyone direct me to the right document for a clearer explanation about the memory allocation options in AIX (INSTANCE_MEMORY, DATABASE_MEMORY AND STMM, BPOOLs, etc).

Did you try the manual?

You can also google for Exploring Memory in DB2 9.5 and Beyond