All about memory

[sandeep.iitk]

Hi,
I am on db2 (64 bit) v8.1.1.112 FixPak "12" 0n AIX. Is there any
limitation for bufferpool size. what should be the RAM size and for a
given RAM size how much we can allocate to bufferpools if it is a
dedicated server.
Anybody knows a good book or some good link for memory management on
64 bit.
In need, Please help

Little help might be a lot to me
Thanks
Sandy

[Richard D. Latham]

"sa**********@gmail.com" <sa**********@gmail.comwrites:

Hi,
I am on db2 (64 bit) v8.1.1.112 FixPak "12" 0n AIX. Is there any
limitation for bufferpool size. what should be the RAM size and for a
given RAM size how much we can allocate to bufferpools if it is a
dedicated server.
Anybody knows a good book or some good link for memory management on
64 bit.
In need, Please help

I'm not aware of any commercially available boxes that can have more
than 4 TB of RAM in them, so don't plan on having a buffer pool bigger
than that :-)

More seriously, I'd have to look, but I think my largest bufferpool
that I'm currently running is around 48GB in an 100GB (+/- a bit) LPAR
on a Power5 machine.

The reason I have it set "so low" is for fall-over. My nodes are
over-provisioned so that if I lose a node, I can fall the DB2 instance
over to one of the other (hopefully, still running <smile>) nodes, and
they'll both "fit" at the same time.

I haven't gotten froggy enough to do any "on the fly" reconfiguration
operations at the time of a fail-over, which leaves me in the "Bog,
thats a lot of RAM sitting there doing nothing practically all the
time" state.

--
#include <disclaimer.std /* I don't speak for IBM ... */
/* Heck, I don't even speak for myself */
/* Don't believe me ? Ask my wife :-) */
Richard D. Latham la*****@us.ibm.com

[sandeep.iitk]

Hi Richard,

Thanks for reply... let me more clear about the specifications. for a
db of around 250 gb, what size of RAM should be suffice for a 64 bit
db2. By RAM size, I mean the lower limit on which application will not
face any problem because of it.

--some doc / book which you can recommend me for memory management
in DB2 (preferable for 64 bit)

Thanks in Advance
Sandy

[Haider Rizvi]

"sa**********@gmail.com" <sa**********@gmail.comwrites:

Hi Richard,

Thanks for reply... let me more clear about the
specifications. for a db of around 250 gb, what size of RAM should
be suffice for a 64 bit db2. By RAM size, I mean the lower limit
on which application will not face any problem because of it.

--some doc / book which you can recommend me for memory
management in DB2 (preferable for 64 bit)

Sandeep, it all depends on what workload you are running. That will
determine the sizing for the solution you need to build (including
your server, # cpus, memory, and disk/storage configuration). These
all go hand in hand, and need to be balanced with each other.

Let's say you size to build your solution with a 4-way Intel based
server. I'd start with a 4GB / core configuration, meaning 16GB for
this server. This should take care of a pretty hefty workload for
either an OLTP or data warehousing environment.

HTH,
--
Haider

[Richard D. Latham]

"sa**********@gmail.com" <sa**********@gmail.comwrites:

Hi Richard,

Thanks for reply... let me more clear about the specifications. for a
db of around 250 gb, what size of RAM should be suffice for a 64 bit
db2. By RAM size, I mean the lower limit on which application will not
face any problem because of it.

--some doc / book which you can recommend me for memory management
in DB2 (preferable for 64 bit)

Thanks in Advance
Sandy

Without knowing quite a bit about the application workload, no one can
really give you anything other than platitudes.

There's a ton of free stuff available at www.redbooks.ibm.com.

I'd give you a URL ... but the site seems to be casters up right now.

--
#include <disclaimer.std /* I don't speak for IBM ... */
/* Heck, I don't even speak for myself */
/* Don't believe me ? Ask my wife :-) */
Richard D. Latham la*****@us.ibm.com

[sandeep.iitk]

Hi Richard,
Thanks for advice. Please send me a URL whenever u got time. Waiting
for it.

Thanks again to all
Sandy