Hi all, I have been advised that the rtkaio library has been discontinued in the SUSE distribution since SUSE 9, so you cannot use the rtkaio libraray on SUSE. Specifically for SUSE do NOT add the following to the cache.cpf file. Also note that the rtkaio library is not needed for IRIS -- only Caché.


Hi Rich, the short story is that I have fixed this an pushed to GitHub. A new container version will appear very soon.

The problem is caused by an unexpected date format in the "Profile" section of the pButtons HTML file.  Year format yy instead of expected yyyy. 

As a workaround, you can open the HTML file in a text editor and edit the date manually to be the expected format. eg

Profile run "24hours_5" started at 00:00:00 on Jun 08 19.

change to:

Profile run "24hours_5" started at 00:00:00 on Jun 08 2019.

Thanks for bringing this to my attention.!

For newer storage, especially all flash, 10,000 iterations will be too quick, change this to 100,000 for sustained read activity -- it should be less than a minute on SSD storage for each step. For example using the above example;

for i in `seq 2 2 30`; do echo "do ##class(PerfTools.RanRead).Run(\"/db/RANREAD\",${i},100000)" | csession CACHEINSTNAME -U "%SYS"; done

hmmm... it worked for me just now.... I did notice when I exported from the markdown editor I used it came across as "\<!--break--\> escaping the slash, but edit to "<!--break-->"  worked OK. on the post about minimum monitoring and alerting solution. To be honest I had not tried until you mentioned it. haha yes switch MD to WYSWIG is a big mistake :(

Hi, I think you have got it. Mark and I are saying the same thing. Sometimes a picture helps. The following is based on some presentations I have seen from Intel and VMware. It shows what happens when multiple VMs are sharing a host, which is why we recommend a reserved instance. But this also illustrates hyper-threading in general.

So to recap; A hyper-thread is not a complete core. A core is a core is a core, hyper-threading does not create more physical cores. The following picture shows a workload going through 4 processing units... micro execution units in a processor. 

One VM is green a second is purple, white is idle. A lot of time is spent idle waiting for memory cache, IO, etc.

As you can see with hyper-threading on the right  you don’t suddenly get two processors, not 2x, and expectation is  ~10-30% improvement in processing time overall. 

The schedular can schedule processing when there idle time, but remember on a system under heavy load CPU utilisation will be saturated anyway so there are less white idle time.

I also received feedback on this from a coworker who has been running workloads on AWS which I think is useful; 

 "I selected the large EC2 instances which used all the available vCPU on underlying processors.   ( AWS would reserve  a few vCPUs  for management functions.  )    Thus,  a AWS 40vCPU system is roughly  equivalent to 20 core with HT  bare metal system of the same clock speed. So right,  If you want the equivalent of 4 VMware cpus , allocate at least 8 vCPUs. Also note the  clock speeds of AWS are slower than what you are typically using.  [ie the servers I use in my on premises benchmarks]. You can  use the specint rate as the comparison." 

For more on the last comment and how to compare SPECint metrics see:




Good question. InterSystems uses AWS for many different workloads and scenarios. There are so many types of server offered, it really is a case where you must test yourself.

As a starting point:

You really need understand just what AWS is giving you. For a list of instance types see the link below.  And note the small print; Each vCPU is a hyperthread of an Intel Xeon core except for T2 and m3.medium.

If you know your sizing on VMware or bare metal with hyperthreading enabled and you usually need 4 cores (with hyperthreading) - I would start with sizing for 8 EC2 vCPUs. Of course you will have to test this before going into production. It would be great if you came back to the community if you came back and commented after your testing.



For more general information I recommend Marks post on EC2 reference architecture.


Mark also noted there is a difference between reserved instances and on-demand.  Reserved is just that – dedicated resources, so you won’t be contending with other VMs. If your requirement is consistent, and you want consistent performance look at the reserved instances.

Hi Anzelem, no. But I m very interested to hear of experience community readers with any HCI solution. Either through the comments or directly.