We all tend to concentrate on the CPU first and the memory second. CPUs, as the "brains" of the machine, does get a high focus and have a lot of extreme technology within it but the RAM is the "guts" of the machine to "feed" the CPU with nutrient data. OK, let us stop the analogy there :-)  Along with reducing the number of CPUs via a lower virtual processor count, we also need to have the CPUs matching the memory - so AIX has a fighting change to localise a running process to its home SRAD and thus have it's data... [More]

Tags:  entitlement lpar ram power7 vm placement virtual aix power6 cpu processor powervm lmb

Time to correct a few assumptions and statements that I made a while back.   Previously I said the POWER Hypervisor decides where to put a Virtual Machine (VM/LPAR) based on the Virtual Processor number (spreading factor). Well, apart from it nearly being right ... I was actually wrong! I got talking to one of these very impressive Hypervisor developers in Germany and he put me right.  In most of my larger machines, I do what I think is fairly normal for creating an VM - like working with a CPU core to RAM ratio that my customers use, like 1... [More]

Tags:  power7 affinity cores chips lssrad core cpu aix srad

I have never really understood why I get peaks and troughs in nmon questions and urgent situations but July seems to be a peak and fortunately I was not at work for a large part of it.  Performance and nmon Questions trend to come in three flavours: really dumb, genuine and mega-urgent critical lets blame the hardware. Let me give you a flavour of each type of question from the last month. Perhaps, reading these will let you avoid the same problem or at least let you learn "you are not alone".   Really dumb "nmon has stopped... [More]

Tags:  cpu service analyser packs aix nmon nmon2web nmon2rrd power7 firmware

Finally, I have the types of memory by POWER7 model double checked. I refreshed the table in part 1 but thought I should make sure every one sees the final version so I have not mislead people.  Only the Power 770/780 and Power 797 have Near memory. All the smaller machine operate a Local memory meaning on the same same POWER7 chip and Far memory for any access to another POWER7 chip's memory.    

Tags:  local power7 far virtual cpu lpar affinity memory powervm near machine

The Hypervisor makes the virtual machine (LPAR) placement decisions and changes during DLPAR. The Hypervisor is part of the Power Systems Firmware.  The POWER7 machines first arrived in the early months of 2010. Since then we have had a lot of field experience with the larger machines with large configurations with large applications and tens of thousands of processes running and in particularly the machines with all three layers of memory - which are the Power 770, Power 780 and Power 795.  From this experience, the POWER developers have... [More]

Tags:  processor power7 cpu vm entitlement powervm virtual aix lpar placement

After you have started and used your virtual machine (VM) for a while, you may decide to change its size using a Dynamic LPAR (DLPAR) change from the HMC (or SDMC or IVM, of course). This has virtual machine placement implications.  When shrinking your VM, the hypervisor will decide which CPU or memory (LBM) to release and it might not select what you think is the obvious choice.  When enlarging your VM, we might thing there is an obvious way to grow in a balanced way but we can't see: 1) where physically our virtual machine is placed in the... [More]

Tags:  ram processor placement power6 power7 powervm dlpar lpar vm entitlement virtual lmb cpu aix

Here is another question from that larger Power 7 machine customer. They have large Virtual Machines (Logical Partitions) and can't see all the CPUs on the screen. This is made worst by Power 7 machines - not a problem with the processors or machines but there are: So many CPUs on larger machines like Power 770/780 and the mighty Power 795 Then the new Simultaneous Multi-Threading (SMT) now means four threads per physical CPU (core). This means lots of physical CPUs and each has four logical CPUs.  So what happens on the screen - you see a... [More]

Tags:  nmon longer physical cpu power powervm aix term

I have just upgraded my EMEA Power Systems Advanced Technical Support internal Wiki Apache Web-server to the very latest AIX level, which is AIX 6.1 Technology Level 6 Service Pack 5 or AIX6.1TL6sp5 for short! Then I noticed that the nmon at this AIX level has been updated - I worked the code for the internal prototype of this new feature some time ago and it has arrived in the official topas/nmon code at this release - C O O L .   The latest release AIX 7.1 service pack has this new options too. The problem: As the numbers of CPU goes up with... [More]

Tags:  power6 power7 tl06 sp5 6.1 aix monitoring topas nmon physical cpu