Shared memory betweens LPARS

[mrn]

Is it possible to share memory between LPARS?

590 has 96GB
LPARS including dual VIO need 98GB

So obviously we can't start all the lpars at the same time.

I was under the impression that whatever your Max is set to is the total physical memory needed in the frame.

so 3 lpars with 32GB Max = 96GB + vio 1GB + vio 1GB = 98GB

Ideas?



Mike

"Whenever I dwell for any length of time on my own shortcomings, they gradually begin to seem mild, harmless, rather engaging little things, not at all like the staring defects in other people's characters."

 

[khalidaaa]

No you can't share memory but you can use PLM (partition load manager) to move memory between LPARs under policies that you specify! that is to answer you first question.

I just didn't understand the last bit you mentioned above! Could you please explain more if that wasn't the answer you expect?

Regards,
Khalid

 

[mrn]

It's OK didn't think you could and it's total Desired must be = or less to total installed not Max

Mike

"Whenever I dwell for any length of time on my own shortcomings, they gradually begin to seem mild, harmless, rather engaging little things, not at all like the staring defects in other people's characters."

 

[p5wizard]

Actually, you also have to count the overhead - every LPAR has a memory page table, whose size is dependent on its max memory size. Then there is the memory for the hypervisor and the memory the box needs for I/O mapping table (don't know exact term for it by heart).

And if the LPARs' "minimum" memory setting is lower than their "desired" setting, you can still fire 'em all up, the last one will get less than the 32GB "desired" though.

Start the vio servers first, you'll use about 2.75 to 3 GB for that (guesstimate for the overhead - pHyp and I/O memory-table size is not based on number of LPARs, they are there regardles how many LPARs).
Then start the LPARs one by one, find out how much mem is left after starting the 2nd big LPAR. That will give you an idea how much is actually needed per LPAR and you may want to distribute that more evenly among the 3 big LPARs (set "desired" to 30,5GB or so).

HTH,

p5wizard

 

[mrn]

I knew about the overhead, but good idea re startup, at least I'll get an idea of how much I'm short.

Same old story vio memory not taken into account in the design doc ;-)

Mike

"Whenever I dwell for any length of time on my own shortcomings, they gradually begin to seem mild, harmless, rather engaging little things, not at all like the staring defects in other people's characters."