HPE 9000 and HPE e3000 Servers
cancel
Showing results for 
Search instead for 
Did you mean: 

rp8400 configuration

 
Mark Harshman_1
Regular Advisor

rp8400 configuration

I currently have two rp8400 servers in a clustered environment, each running as a single partition. Each server has 12 GIG memory, and 12 CPU's on 3 cell boards. (4 and 4 each). We are getting ready to bump that by an additional 2 CPU's, 2 GIG memory, and adding the 4th cell board to each. I was requested to consider adding our new 4 GIG of memory to one of the servers (plus 2 CPU's and new cell board), and no memory to the second, but still add the 2 CPU's and cell board. I was told by a local HP guy that this was not a recommended configuration, and also we would have to re-allocate the 12 GIG of memory on the 2nd server to cover all 4 cell boards. This would then have us in a situation where we have 4 CPUs, 4CPUs, 4CPUs, 2 CPUs, plus 3 GIG, 3 GIG, 3GIG 3 GIG accross the 4 cell boards. i wanted to double check this and get any additional info i could. Also, if your aware of any doc you could point me to regardning this, i would apprecaite it.
thanks
Never underestimate the power of stupid people in large groups
8 REPLIES 8
Mister_Z
Frequent Advisor

Re: rp8400 configuration

Mark,

is very advisable that the two nodes own the same resources.
I work for HP
Joshua Scott
Honored Contributor

Re: rp8400 configuration

Mark,

It's reccomended that you use the same amount of memory across all the cell boards. read the doc:

http://docs.hp.com/hpux/onlinedocs/5187-4534/5187-4534.html

-Josh
What are the chances...
Michael Steele_2
Honored Contributor

Re: rp8400 configuration

Well, I'm either missing the point or something because I don't see partitioning mentioned and these guidelines are more applicable to having identical nPars.

But what I'm infering from your posting is 2 servers without any partitions that are clustered together via some unprovided application. And this is the only thing that bothers me; The clustering. Epecially in a MC/ServiceGuard cluster.

So please clarify these two issues:

a) Partitioning and what configuration?
b) What application used to cluster?

The long and short of it is, if no partitioning in two separate servers then build them as you like because there are no limits to resource configuration.

But depending upon the type of clustering, especially in a High Availability failover environment cluster, then clustering usually means having identical servers.

The only exception might be to a third disaster recovery node that has been cut down for lack of use.
Support Fatherhood - Stop Family Law
Mark Harshman_1
Regular Advisor

Re: rp8400 configuration

Sorry, each server is a single partition. We are using serviceguard to cluster. Running HPUX11i. I also read where memory should be added in powers of 2, or we could experience performance degradation. We are already not meeting that guideline.
Never underestimate the power of stupid people in large groups
Joshua Scott
Honored Contributor

Re: rp8400 configuration

I don't have much experience with MC/SG, but from my understanding, the systems should be identical, correct? if so, then you shouldn't add more memory to one than the other.

I think that it is possible to add a cell board with no memory, but you will be adding a huge load on the bandwidth of the crossbar backplane because those CPUs will have to go through the backplane every time they access memory.

also, just because you are not following some of the configuration guidelines right now without a noticeable performance hit, doesn't mean it's a good idea to to stop following others. there should be memory evenly distributed across the cell boards

-Josh
What are the chances...
Saurav_1
Valued Contributor

Re: rp8400 configuration

Hi,

I just copied it from documentation for U
____________________________________________
Performance and High Availability:-
For high availability reasons, a cell should contain at least 8 memory DIMMs (Dual Inline Memory Modules) for a minimum of 4 GB RAM. For the best performance, all the cells in a partition should contain the same amount of RAM. This is because all the memory in a partition is fully cache-line-interleaved, meaning that each cell's memory forms part of a common pool used by processes running on that partition. If one cell in the partition has more memory than the others, that cell will contribute disproportionately to the pool and the connections to and from it will be overworked, degrading performance.
_________________________________________

Saurav
Saurav_1
Valued Contributor

Re: rp8400 configuration

Based on my above comment this can be confirmed that ur server's each cell is having 4 GB of RAM. Its ur good decision how to go for the upgrade. I think. U shud decide not to upgrade the second server as per your present plan. or order enough hardware for it.

Saurav
Jeff Schussele
Honored Contributor

Re: rp8400 configuration

Hi Mark,

Although it's highly, highly recommended that cluster members that will be failover pairs be identical - it's not mandatory.
I've had oddball clusters in the past. One I remember was a V-class, L-class & a K-class.
We had to setup the failover policy so that there was no way to swamp the K or the L if the V failed. It worked, but it wasn't pretty.

As to the RAM - yes - you'll suffer a performance hit if the cells aren't matched.
Again it will run that way - just not optimally.

My 2 cents,
Jeff
PERSEVERANCE -- Remember, whatever does not kill you only makes you stronger!