AIXpert Blog is about the AIX operating system from IBM running on POWER based machines called Power Systems and software related to it like IBM Systems Director, PowerVM for virtualisation and PowerSC for security plus performance monitoring and nmon
The SDMC Redbook is available now - actually on the announcement date - so some one was planning ahead! IBM Systems Director Management Console: Introduction and Overview , SG24-7860-00 http://www.redbooks.ibm.com/abstracts/sg247860.html 6.9 MB and 430 pages
This is a new feature of starting with AIX 5.3 TL9 and AIX 6.1 TL2. svmon will now report a new metric called "available memory." This is the amount of memory available to applications. It includes memory in the file cache. The basic idea is that a user can consume the "available memory" without causing the system to start paging to paging space. Once "available memory" is depleted, AIX will have to start paging out to paging space. To get svmon to display the available metric, you can specify the ''-O summary=basic" option. There are a... [More]
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]
Here is a recovery procedure for replacing a failed client disk on a Virtual IO server. It assumes the client partitions have mirrored (virtual) disks. The recovery involves both the VIO server and its client partitions. However, it is non disruptive for the client partitions (no downtime), and may be non disruptive on the VIO server (depending on disk configuration). This procedure does not apply to Raid5 or SAN disk failures. The test system had two VIO servers and an AIX client. The AIX client had two virtual disks (one disk from each... [More]
On Power6 the largest machine was the Power 595 with 64 Physical CPUs (cores) across eight CPU books in the machine - each CPU book having 4 Power6 chips and so 8 CPUs (Power6 is a dual CPU chip design). However, with Power7 that has stepped up to 256 CPUs across the same eight CPU books with four chips but with 8 CPUs each so that is 32 CPUs per book. I might be stating the obvious but memory access to memory directly attached to the Power chip on which your process is running is slightly faster than memory access via a Power chip near by... [More]
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]
I just noted two great new things to help those running Java on AIX and it seems hard to avoid Java these days! I was just monitoring a customer machine with 1500 WebSphere Application Servers (WAS) each with 100 to 150 threads so roughly 200,000 threads!!! More impressing was that just 20 Power7 physical CPUs was supporting this workload. So here are two things that can help: 1. Java Performance Advisor (JPA) Available for download to anyone on IBM DeveloperWorks website. This is a powerful new tool to help people identify opportunities to... [More]
Ganglia is a open source performance and configuration tool that collects data from a tiny daemon on each OS and then creates a Web server based graphical tools to draw performance data and show the configuration. With a few add-ons, you can dynamically decide the historical data you want graphed and with POWER add-ons you get the PowerVM stats for shared processors, Entitlement, physical CPU use etc. Under the covers it is using the amazing rrdtool so you can extract the data for other uses and it automatically space manages the data. By... [More]
While I was installing a re-purposed POWER6 machine over the weekend, got round to installing my Dual Virtual I/O Servers, from DVD and then upgrading from there and I noticed a new service pack 2 for the latest VIOS version. It must have sneaked out without me noticing and there is a Interim fix too. The VIOS 22.214.171.124-FP24 SP2 Readme highlights lots of fixes including some for the Shared Storage Pool feature. A feature that I have been using and talking about (see this blog for more information). This got me thinking! I talk to lots... [More]
Warning: touchy feely comment coming up! I have always found it odd that IBM markets the Hardware = POWER7 a lot and very little marketing on the Operating System = AIX7. Personally,
I have more good feelings and positive vibes for AIX operating system
because I log in to every day and use it for hours than I do for the
POWER hardware running it. I very rarely go to the machine room and hug the machine! Does anyone else feel this way or am I sadly alone? Put
it another way would you spend two Dollar Euro Pounds (all increasingly
You may have seen comments or even presentations with a few slides on VIOS Next Generation or VIOS NextGen in the past year. I did at the Power Technical Universities and was very interested. Well, the first phase has been release but you may well have missed it as it appears as VIOS 126.96.36.199 FixPack 24 Service Pack 01 - not a catchy title and it slipped out below my radar! It is a regular service pack for the current VIOS and include some other features and fixes too. The first thing you have to note is that only a few features are available... [More]
I just realised that I got help from the AIX developers to explain the output of the mpstat -d command for my POWER7 and Affinity Technical University sessions in Miami and Copenhagen that I never passed on to every one. In an earlier blog we examined some mpstat columns but skipped others. The nearly undocumented mpstat stats are: S0rd, S1rd, S2rd, S3rd, S4rdand S5rd. In the AIX manuals it states: S0rd = The percentage of thread re-dispatches
within the scheduling affinity domain 0.
And likewise for the other numbers - but what does... [More]
Starting with AIX 5.3, you can get the process tree showing all the children of a particular process in a tree format. This is a part of the Linux affinity push: Example: $ ps -T 119016 PID TTY TIME CMD 119016 - 0:00 sshd 1015808 - 0:00 \--sshd 418006 - 0:00 \--ksh 913436 pts/0 0:00 \--ksh 639072 pts/0 0:00 \--ps
*** STOP PRESS *** - See the update in red at the bottom.
I was asked this lots of times at the recent POWER Technical Universities in Orlando and Athens.
Compared to a low numbers of local disks
The LUNs on a SAN disk subsystem with caching are very fast - even a simple test like AIX install times have halved. In addition, you don't have to fiddle about with stripping AIX Logical Volumes across disks or retro fit this to rootvg Volume Group filesystems after the install.
Compared to a... [More]
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]