AOS and number of cores in AX 2012

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Posted on by DaxNigel

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Historically (AX2009 and before) the number of cores recommend for an AOS has always been 2, this is because the AOS code was not optimized to utilize more than 2 cores. With the introduction of AX2012 I am wondering what the optimal number of core are for an AOS. Can the AOS utilize more than 2 cores? Is there an limit to the number of core the AOS can utilize? Is there an optimal amount?

There is very little guidance that I can find on this topic. If anyone has any references to materials that discuss such topics or know the answers that that would be good. Also what are people experiences on the topic.

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rudra 6,534 on at

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To my experience 1 AOS will not use more than 2-4 cores but with load balancing on multiple AOS we can make the AOS to use as much cores.

Also refer:-

blog.mohamedaamer.com/.../microsoft-dynamics-ax-2012-day-in-the-life-benchmark

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Denis Patrakov on at

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Axapta 3.0 employs MicroQuill SmartHeap library v6.0.1 for it's dynamic memory (heap) management, which is optimized for single core (at most hyperthreaded) processors. I personally checked kernel builds from 3.0.1951.17 through 3.0.1951.7609 (shipped since October 2002 through October 2006), and the library version used in the kernel was exactly the same. Note that there was also SmartHeap/SMP v6.0.1 that was optimized for Multi-CPU machines and had been announced by May 2002, yet Axapta 3.0 kernel used less sophisticated (and probably less expensive) version of the library. I believe that it is the choice of the heap management library version that led to poor AOS scalability in terms of CPU cores.

Dynamics AX 4.0 kernel (as I've found out) uses SmartHeap/SMP v8.0.0 library that is optimized for SMP systems, so 2-core per AOS rule has been invalid for Dynamics AX since v4.0 (at least in terms of heap management). That is more, concurrent sessions' management model has changed dramatically. Axapta 3.0 AOS used to launch a dedicated thread per user session plus a few threads for the AOS itself. AX 4.0 has switched from the proprietary AOCP client-server communication protocol to RPC and thus it hosts a pool of RPC worker threads to run concurrent client sessions. In Axapta 3.0 if you have 100 concurrent client sessions per AOS then you have about 105 AOS process threads. In AX 4.0 you have about 15-25 AOS process threads for the same number of concurrent client sessions. Less threads means less heap locks and a better Multi-CPU scalablity.

According to some inside information, AX 2009 kernel has switched from the proprietary SmartHeap library to the standard Low-fragmentation Heap introduced in Windows Server 2003. Along with the introduction of the x64 AOS kernel version it means that AOS scalability is constrained by the hardware rather then by the kernel architecture.

Consequently, the official Dynamics AX 2012 Infrastructure Design Workshop switches from sessions per AOS to sessions per CPU core. In the official 'Day in the Life' AX 2012 Benchmark 5 rich client-dedicated AOSes host 4040 concurrent user sessions, 3 EP-dedicated AOSes host 1095 concurrent EP sessions. In the official 'Enterprise Portal' AX 2012 Benchmark 2 AOSes host 10000 concurrent EP sessions. They all employ 12-core machines but you bet they scale efficiently enough to use all those cores.

A (conservative) rule of a thumb is now: 60 concurrent sessions and 5k document lines (whichever comes first) per core for rich client-dedicated AOS, 200 concurrent sessions and 10k document lines per core for EP-dedicated AOS (without Batch/AIF/Workflow processing), and 15k document lines per core for Batch/Services & AIF/Workflow-dedicated AOS. A typical AOS host is 4-12 cores per AOS instance.

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DaxNigel 2,574 on at

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This is good information. I have one follow on question: What does it mean by document lines?

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Denis Patrakov on at

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Number of document lines is a total number of weighted lines for all the application modues: general ledger journal lines plus purchase/sales order lines (with a multiplier of 2) plus packing slip lines (x2) plus invoice lines (x2) plus production order lines (x4) plus AIF document lines (x8).

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AHSAN MINHAS 50 on at

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Hi,

I am little confused over the new architecture of AX 2012 R2. We are also going to implement 2012 R2 with 50 concurrent users both ENT and FUN users on a Visualization environment (VMware vSphere 5 Enterprise Plus). Can you please suggest how many cores we need on each server VM including SQL Server 2012 R2, AOS, Web Server and Remote Desktop Server and how much RAM and storage will be needed for them at an average. For non-production (test servers), how many cores would be required for AOS and Database Server.

Please suggest to eliminate the created confusion by vendors

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Denis Patrakov on at

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Sorry, you can't do (adequate) AX infrastructure sizing based only on the number of concurrent users.

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rudra 6,534 on at

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Gloomie,

With one AOS how many users can accomodate, if you could tell with minimum and maximum counts of users will be more helpful and i hope the same counts will be applied for these versions AOS's as well AX2012, AX2012FPK,AX2012R2&R3.

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Martin Dráb 237,878 Most Valuable Professional on at

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You can have one thousand users doing completely nothing or one user running an extremely expensive calculation. You can say that the AOS can handle one thousand users and it's not sufficient for a single user at the same time. The number of users alone simply doesn't mean anything.

The metric with document lines tries to approximate actual users' activity.

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rudra 6,534 on at

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Martin i agree, lets say 100 users were actively using the AX regularly in this case how many AOS i should have to accommodate the load

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Martin Dráb 237,878 Most Valuable Professional on at

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You still haven't answered anything - what "regular use" means is completely relative. Does each user generates 1 or 1000 transactions per a time unit?

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