Before we look further in to memory affinity we need to recap on the scheduling of processes and process threads of a multi-threaded process to simultaneous multi-threading (SMT) processors like POWER7.  POWER5 and POWER6 had two modes of SMT off (one thread) and on (two threads) - with SMT=on two processes run at the same time (in the same clock cycle) on the CPU-core but using the different logical units inside of the CPU-core (units like the integer maths (there is more than one), floating point maths (there is more than one), compare and... [More]

Tags:  logical core powervm vp aix smt power7 processor power

N-Port Id Virtualisation (NPIV) and virtual Fibre Channel adapters - like high speed physical adapters (see an earlier blog) do require memory to operator at full speed.  NPIV effectively turns the Virtual I/O Server (VIOS) into a kind of virtual SAN switch where packets are passed through with no changes from the physical adapter to the client Virtual Machine (LPAR).  I found it very hard to find a recommendation in the documentation but was given a rule of thumb.  As before it should be noted that starving the VIOS and the Hypervisor of... [More]

Tags:  thumb power7 of rule npiv adapters aix power virtual

We all know that a VIOS level is only fully supported for 2 years ... right!   If you have problems with an older VIOS, you may be asked to upgrade to a supported level before a fix can be issued.  Most teams run a dual VIOS configuration to allow painless and live upgrades for just this reason. The other reason is to survive a VIOS crash but I have never had a VIOS failure but that would be because I don't go fiddling with them nor adding unsupported software. I quickly upgraded my POWER7 VIOS from 2.1 to the latest VIOS level and made a... [More]

Tags:  power power7 systems aix vios

There is a potential problem with AIX display of local time which might occur around the transition to standard time this coming weekend. If the problem occurs, in most cases the only impact is that AIX displays local time incorrectly for a day or so around the transition to or from daylight savings time. AIX displays standard time when it should display daylight savings time or vice versa. Of course, while local time is being displayed incorrectly, if some local time is provided to an application (eg, changing the AIX system clock,... [More]

HACMP recently announced support for the following: HACMP Support for Live Partition Mobility Click on the above linked text for full support details.

Configuring MPIO for the Virtual Client , describes how to set up Multi-Path I/O boot disks for AIX clients of the virtual I/O server. There some considerations for booting off the SAN. The "pro's" include: IBM supported configuration Flexibility The "con's" include: If the SAN fails Can not capture an AIX dump file (Consider putting dump space on an internal disk) Lose the ability to diagnose the failure from the server side. Updating MPIO on the AIX client may be disruptive (depends on MPIO vendor/version) "Momentary SAN stalls" can cause... [More]

Tags:  administration

Federico Vagnini has written pGraph, an excellent "freeware" tool for viewing AIX and Linux. performance graphs. The viewer works with multiple input formats, including * nmon (either on AIX and on Linux) * vmstat -t on AIX * topasout (AIX's continuous performance data collector) * topasout on AIX * iostat -alDT on AIX * HMC's data collection extracted using lslparutil command * Workload Partition data collected on AIX6 (currently tested only on Open Beta) You can download pGraph from... [More]

IBM is opening up AIX 6 for beta testing.You can download a copy of AIX 6 and test iton your servers. For more information, see http://www-03.ibm.com/servers/aix/6/preview.html

In 2007 the Daylight Saving Time start/end dates will change in the United States. The new start date is the second Sunday of March; the new end date is the first Sunday of November. For more information, see "Managing the Time Zone Variable" at http://www-1.ibm.com/support/docview.wss?uid=isg3T1000252 You'll need one of the the following APARs: AIX 5.3 = IY75211 AIX 5.2 = IY75213 AIX 5.1 = IY75214 AIX 4.3 see workaround in the "Managing the Time Zone Variable" Some of the more current AIX releases already have this patch. You can use the... [More]