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AME Memory Expansion - What is a typical Expansion Factor?
Active Memory Expansion (AME) can second in my Top Ten Technologies to be business as usual in the next few years from hundreds of votes world wide. It is available on Power7 machines with AIX 6.1 TL4 SP2 onwards and AIX 7, of course. This allows memory to look at lot bigger than it actually is - to allow more LPARs to be running on a machine or giving headroom for boosts performance. The usefulness of AME is all down to the Expansions Factor (EF) - which is based on the compression ratio achieved for memory pages. If the EF very low then you... [More]
Tags: ame expansion factor power7 ram aix memory |
Local, Near & Far Memory part 7 - VM placement also needs RAM
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: processor lpar power6 ram vm powervm power7 virtual aix placement lmb entitlement cpu |
Local, Near & Far Memory part 8 - Dynamic LPAR changes can mess up your 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: vm placement aix processor power7 virtual cpu dlpar power6 entitlement ram lmb lpar powervm |
AIX Memory Usage - or - Who is using the memory and how?
Common question: I see XX% of Used Memory but I don't know who is using it and how? A simple question but there is no simple answer as memory use if complex. nmon then hit "m" will quickly show you a few big uses of memory as below: The shared memory used by lots of applications like DB2 and Oracle - check the SEGSZ for the size. The Owner column usually tells you what it is used for like the oracle user for the SGA or db2inst1 for the DB2 buffer cache. Then it is down to the processes and this gets... [More]
Tags: memory aix use power svmon nmon ram ipcs |
