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
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]
We have all probably seen or used the topas CEC on-screen view (topas -C command). This is started while logged into one AIX Virtual Server (LPAR) and shows all the other AIX or VIOS (as it is based on AIX) Virtual Servers of a single Power Server. Here is a reminder - this is on-line, on-screen and updated every 10 seconds or so: Here my Virtual Servers are called purple<something> and below the top machine summary we have a line for each Virtual Server and stats like AIX release, memory use, CPU stats (PhysB is the Physical CPU time... [More]
This is a follow on from yesterdays blog due to Chris Gibson highlighting a question/concern from one of his customers in Australia.They were comparing Power6 and Power7 and the utilisation numbers from the SMT Logical Processors and the graphs look different. I looked at some nmon data (what else!) and yes they are looking different and then I ran a simple generated workload test and duplicated the graphs. Below I then explain them - once again these are my personal observations rather than an official AIX developers insider statement. I... [More]
Hi, I just release a fifth hands-on movie this month and on this interesting topic. You can find the movie here: Shared Storage Pools 2 - Thin provisioning, monitoring free space + Alerts Shared Storage Pool Thin provisioning is pretty cool and saves a lot of disk space . Effectively the 100's of GBs of unused disks space in 100's of Virtual Machines (LPARs) are bought together in one place in the Shared Storage Pool and then can be used for real. All this without the use of clever disk subsystems. The risk is that you use all the disk... [More]
The below URL takes you to the top of the Systems Director 6.3 online documentation http://publib.boulder.ibm.com/infocenter/director/pubs/topic/com.ibm.director.main.helps.doc/fqm0_main.html As a rule I use Firefox 3.6.24 all the time for my browsing as it works well for Systems Director and Hardware Management Console (HMC). Later Firefox versions have "variable" results which re frustrating and that just slow me down. The Firefox developer when mad and got to version 8 suddenly over what appeared to be a few weeks but have realised... [More]
Finally, I found the time to try this new exciting feature and it was really simple to create and operate. I captured movie footage of my first attempt and it all worked (once I removed my spelling mistakes in commands). It only took two commands. So the technology has advanced concepts but it really easy to use, COOL! Some of the commands come with long option names like "-custername". A quick misquote from Star-Trek, never goes wrong: "It is UNIX Jim, but not as we know it!" One command to create my cluster,... [More]
AIX or VIOS Start-up Memory Problems I have been working with a couple of customers that have a newly setup AIX Logical Partition (LPAR) that fails to start due to not having enough memory. The common factor is that the LPAR for AIX (or VIOS) includes a good number of what I call "high speed" adapters like 10 Gbps Ethernet, or 4 Gbps or 8 Gbps Fibre Channel adapters. They tend to have multiple adapters of each type for redundancy and throughput. For example, trying to start the LPAR with 1 or 2 GB of memory but it turned out they need... [More]
IBM announced lots of Power Systems software yesterday but the official announcements are pretty thin on the details. I have many Twitter tweets asking "What the heck does that all really mean?" and the official statements are marketing messages and not technical information like:
How do you get that working?
What are the pre-reqs?
What are the actual commands?
What does the Graphical User Interface look like?
How does that help me as a System Admin person?
Most AIX system administrators use: smitty tcpip to add a hostname, IP address, network mask, gateway and DNS server setting to get the virtual machines (LPAR) and AIX on a network. And as a side benefit so we don't need to use the ghastly VTERM console any more as ssh or the dreaded unsecure telnet (just don't do it) can now be used - as the root user:
# smitty tcpip
Minimum Configuration & Startup
Use DHCP for TCPIP Configuration & Startup
I thought I should summarise the long eleven part Local, Near & Far POWER7 Affinity series. 1) Placement: Find out the layout of your boxes CPU and RAM and if the RAM is evenly distributed across available DIMMs Find out the placement of your Virtual Machines (LPARs) with lssrad -av - or - topas -M 2) SMT4 : Expect POWER7 SMT4 CPU use to “look” different POWER5 & 6 have two equal threads POWER7 shuts down threads 3 & 4 and even thread 2 - when there is not enough processes running. 3) Entitlement : Only set minimum Entitlements,... [More]
This week I spent 4 hours with a customer covering many advanced WPAR topics and took way a bunch of questions that I had to check the answers and ask the WPAR developers themselves to be sure I had the right answers. If the questions were not clear to my customers and I did know initially know the answers then there may be others with similar issues so I thought I would share the answers with everyone. 1) Workload Partitions - What is the road map? Well, I am not going to make announcements on a blog for sure. If you are new to WPAR, I can... [More]
LPAR2RRD Briefly, Based on the same HMC data that Systems Director gathers is LPAR2RRD but it saves the data in the famous and excellent rrdtool database and graphing tools. This is a supported by the developer which is Pavel Hampl, IBM Czech republic, as a personal project tool and does a very good job. For more details and a sample website to look round see - AIX Wiki page for LPAR2RRD I note this is a sourceforge.net project now - See the above for a link to the project and code Cut from that AIX wiki page for the project here (all... [More]
I am using the VIOS Shared Storage Pools more these days and it reduces my system admin time and I really like the Thin Provisioning feature as I have limited SAN disks. Any way, I dusted off an machine that I did my initial investigation on and decided to rebuilt the cluster (of one VIOS) now that I know what I am doing :-) The command : cluster -create -clustername galaxy -repopvs hdisk2 -spname atlantic -sppvs hdisk3 hdisk4 hdisk5 -hostname diamondvios1 fails with "PV IS IN USE hdisk4". PV meaning Physical Volume. Yes,... [More]
The official rPerf rating (relative performance rating of Power based machines) are available in the pSeries, System p and now Power Systems "Facts and Features" documents that are on the IBM website. It is best to use Google for them (searching for "pseries Facts and Features" works for me). You may want to know the rPerf rating for your LPAR and an LPAR that is not one of the officially rated numbers of CPUs/Cores. There may be ratings for 8 and 16 CPUs but your LPAR has 13 CPUs! Well, you can run the rperf script on the... [More]
I have been looking at some nmon data from an IBMer looking into a customers machine. The virtual machine (LPAR) is running the Oracle RDBMS with 75 dedicated CPUs - on a POWER7 Power 795 at 4 GHz.
The Excel spreadsheet is quite scary at 144 MB thank goodness my Thinkpad has a SSD but not the record by a long way. Too many data save points can ready add u and so too can lots of processes if you are saving process data. Also with 75 CPU and SMT=4 that is 300 Tabs for Logical CPU, 300 for PCPU and 300 for SCPU and that... [More]