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Increase Extended memory in SAP.

former_member268919
Participant
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Hello Experts,

Our target is to increase Extended memory(em/global_area_MB) this is because we are going to extended the rdisp/plugin_auto_logout from 30 min to 60 min. Also we are going to increase the ICM TIMEOUT parameters from 900sec (15 min) to approx 1800 sec (30 min) so this may increase the concurrent users into the system.

Just to brief :

The current scenario for 650-700 concurrent users are logged in at a same time via Web platform with auto logout timer of 1,800 sec. = 30 min.

Regarding Memory Consumption, the ITS server memory is occupying  3GB of total 8GB.

The ITS uses memory of the extended global memory area (EG) which is configured to 8GB via the parameter em/global_area_MB.

Even to protect the WebAS from running out of memory there is a threshold set so  if the amount of memory used reaches watermark, further ITS sessions will be refused. The parameter itsp/max_eg_mem_percent (Set to 80%) determines this limit, default value 80. This means that no more ITS logons are possible as long as the amount of free memory is less than 20%.
We have checked the profile parameter icm/max_conn(Maximum number of open connections at one time) value is 1000. This means 1000 users can logged in at a same time.

We need to increase the system memory a little more to avoid any performance issues.

Kindly suggest.

Thanks.

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Answers (1)

Answers (1)

Matt_Fraser
Active Contributor
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Hi Trev,

It would help others to make more meaningful suggestions if you can describe your environment a bit. What is the OS platform for the server? What release of the software is it running? Are you planning to add additional physical memory to the server?

Regards,

Matt

former_member268919
Participant
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Hello Matt,

Thanks for reply.

SAP SRM 5.0

Linux x86_64

Oracle 11g

Yes planning to add additional memory. But how much?

Thanks.

alexander_bolloni
Contributor
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Hello,

just a comment:

em/global_area_MB does not control the total size of EM memory (the relevant parameter for that would be em/initial_size_MB ) but it specifies only the portion INSIDE the total EM area which will be reserved for Extended Memory Global (EG memory), which is "normal" EM memory but which is shared between all work processes (whereas normal EM memory is always only usable by one specific user session/ one work process).

I must admit I am not familiar with ITS requirements on EM, so cannot give an estimation. The only advice I can give is: if you increase EG memory area via the global_area_MB param, because you foresee  a higher EG requirement from ITS, correspondingly increase em/initial_size_MB as well (provided you have enough RAM on the server), otherwise this will reduce the amount of EM available for normal ABAP user sessions.

Regards,

Alex


Matt_Fraser
Active Contributor
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How much memory to add can be subjective. There are various tools (http://service.sap.com/quicksizer) and services and guides () to help you figure this out. However, you need to look at the hardware you are using, and what your plans are for it.

SRM 5 is quite old. Indeed, extended maintenance for it runs out at the end of this month. I know, because we are running SRM 5 ourselves, and we are in the midst of a project to upgrade it to SRM 7.

How old is the hardware you are running it on? Are you planning to replace it soon? In our case, we are also replacing the hardware with a new model, and in the process going from 16 GB of physical RAM to 64 GB of physical RAM. Our system ran acceptably in 16 GB -- not super fast, but acceptably -- and under current usage patterns it doesn't really need 64 GB. However, when purchasing the new hardware, it came with 48 GB as a baseline, and the difference to upgrade it to 64 was minimal. So, that is our new standard for production servers (48 GB for DEV and QAS servers). Even 48 GB is more than this system needs, to be honest. However, we also envision expanding usage of the system to more users in the not-too-distant future, so this is giving us headroom.

So, given that these higher amounts of RAM come pretty much standard on new hardware models, and the cost is not that significant, it doesn't make a lot of sense to waste time precisely sizing our needs when we know from experience that our needs are less than this.

On the other hand, if you are not changing your hardware, but just planning to add RAM to the existing server, then you may need to consider the cost. Still, though, I would think of the capacity of the motherboard as more important than the cost (i.e., how may DIMM slots and what is the maximum size of DIMM per slot?). If you will be keeping this hardware for more than another couple years, then I'd look into the cost of maximizing the RAM that can go in it.

Another data point is that we are not running with nearly as many concurrent users as you. Our numbers are more in the couple dozen at a time, with peak loads at certain times of year perhaps around fifty or sixty or so.

I would recommend having a look at Notes 941735 (SAP memory management for 64-bit Linux systems) and 885580 (Integrated ITS: Configuration Parameters), and also the various Notes for ITS and ICM configuration listed in the references of Note 885580.

Beyond this, I can't really make recommendations, as our system is running on Windows/SQL Server.

Matt_Fraser
Active Contributor
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For an SRM system, there won't be very many normal ABAP user sessions, although it is an ABAP system. Almost all of the users, other than system administrators, will be ITS plugin users.