Random Short Take #63

Welcome to Random Short take #63. It’s Friday morning, and the weekend is in sight.

  • I really enjoyed this article from Glenn K. Lockwood about how just looking for an IOPS figure can be a silly thing to do, particularly with HPC workloads. “If there’s one constant in HPC, it’s that everyone hates I/O.  And there’s a good reason: it’s a waste of time because every second you wait for I/O to complete is a second you aren’t doing the math that led you to use a supercomputer in the first place.”
  • Speaking of things that are a bit silly, it seems like someone thought getting on the front foot with some competitive marketing videos was a good idea. It rarely is though.
  • Switching gears a little, you may have been messing about with Tanzu Community Edition and asking yourself how you could SSH to a node. Ask no more, as Mark has your answer.
  • Speaking of storage companies that are pretty pleased with how things are going, Weka has put out this press release on its growth.
  • Still on press releases, Imply had some good news to share at Druid Summit recently.
  • Intrigued by Portworx and want to know more? Check out these two blog posts on configuring multi-cloud application portability (here and here) – they are excellent. Hat tip to my friend Mike at Pure Storage for the links.
  • I loved this article on project heroics from Chris Wahl. I’ve got a lot more to say about this and the impact this behaviour can have on staff but some of it is best not committed to print at this stage.
  • Finally, I replaced one of my receivers recently and cursed myself once again for not using banana plugs. They just make things a bit easier to deal with.

EMC – DIY Heatmaps – Updated Version

I’ve patched the DIY Heatmaps script, fixing a problem with the table names generated in the database files. You can download it from the Utilities page.




EMC – DIY Heatmaps – Updated Version

Mat has patched the DIY Heatmaps script, fixing a problem with current model VNXs and updated naviseccli whereby using the –get_drive_type –display_drive_type options of the heatmap script would cause a JavaScript error in the resulting heatmap HTML file. You can download it from the Utilities page.

EMC – DIY Heatmaps – Updated Version

Mat has updated the DIY Heatmaps script to support SAS-type Flash drives. Download it from here, take it for a spin and let us know what you think. And tell your friends.

EMC – Unisphere / Analyzer weirdness

Mat came across a weird problem with Unisphere the other day while he was trying to retrieve some nar files for EMC to look at. Normally I like to post solutions up here but in this case I don’t know what the solution is. Previously, it was my understanding that we could retrieve access multiple nar files from multiple arrays in the same domain via the one Unisphere session. This doesn’t seem to be the case anymore. As background, we run 4 CX4-960s and a CX4-240 in a single Unisphere domain. These arrays were all upgraded to 30.525 recently.

Normally, I’d login to one of the arrays and go to Monitoring -> Analyzer and then Retrieve Archive. So far, so good.


But when I change the “Retrieve Archive From:” selection, I get the following.


Notice that I’m trying to retrieve files from the array serial number 0260, but I’m still seeing 0679, even after hitting Refresh. Maybe it’s Unisphere on that array, let’s try another.


Ok, I’ve logged on to array 0260 and can now retrieve the files I want. But do I still get weird behaviour? Yes, yes I do.


If anyone has any ideas, I’m all ears. I think Mat is going to log a call at some stage.


Dell Compellent – ESXi HBA Queue Length

This is a quick post that is more for my reference than for anything else. When I had the Compellent installed, Dell passed on a copy of the “Dell Compellent Storage Center Best Practices with vSphere 5.x” document (Dell P/N 680-041-020). One of the interesting points I noted was around modifying the queue depth, and where that should be done. As with any best practice document, there are going to be factors that may influence the outcomes of these activities in a positive or negative fashion. In other words, YMMV, but I found it useful. As always, test it before launching into production.

Firstly, set the HBA queue depth to 255 via the HBA BIOS. The thinking here is that the VMkernel driver module ultimately controls the HBA’s queue depth. Now, set the queue depth on the driver module. I use QLogic HBAs in my environment.

To find the correct driver name for the loaded module, run the following command.

esxcli system module list |grep qla

The output should be something like qla2xxx

Now run the following command.

esxcli system module parameters set -m qla2xxx -p "ql2xmaxqdepth=255 ql2xloginretrycount=60 qlport_down_retry=60"

Note that you can also set it via Disk.SchedNumReqOutstanding (DNSRO), where the default value is 32. Keep in mind that this setting is only enforced when more than one VM is active on the datastore. This is a global setting too, so if you’ve set the DNSRO value to 64, for example and you have two datastores in place, one with 4 VMs and one with 6 VMs, each VM will get 64 as the queue depth value. VMware recommend that this value be set to the same as the VMkernel module driver value.

You can also modify the queue depth in the Windows guest OS my modifying the registry settings of the OS.

In any case, go check out the document. It’s one of the more useful white papers I’ve seen from a vendor in some time.

EMC – DIY Heatmaps – Updated Version

Mat has updated the DIY Heatmaps for EMC CLARiiON and VNX arrays to version 4.01. You can get it from the Utilities page. Any and all feedback welcome.

Updates and Changes to the script

  • Add database storage / retrieval for performance stats. The database size will be approximately 2.1 x the size of the NAR file based on the default interval of 30 minutes. On my PC it took a bit over 9 hours to process 64 NAR files into a database, the NAR files were 1.95GB and the resulting database was 4.18GB. However running the script over the database to produce a heatmap only takes seconds.
  • Changed to use temporary tables for transitional data.  This should slightly reduce the size of the database file, as the temporary data is not written to disk.
  • Changed the way the script processes multiple NAR files, the script previously bunched all NAR files into a single naviseccli process, this was problematic if you were processing multiple large NAR files, the script now processes them one at a time.
  • Add command line options:

–output_db                               Output the processed NAR file to the nominated database

–input_db                                  Use the nominated database as the source of data for the heatmap

–s_date                                       Specify a start date/time must be in the format (with quotes if specifying date and time “mm/dd/yyyy hh:mm:ss”

–e_date                                       Specify an end date/time

–retrieve_all_nar                     When retrieving NAR files from the array, you can now retireve all nar files (it wont overwrite files already downloaded)

–process_only_new                 If you are downloading NAR files, only process files that haven’t been downloaded previously

–max_nar_files                        Set the maximum number of files to download and process


Please let us know if you find any bugs or problems with the script, or if you have any further suggestions for changes and enhancements.



EMC – DIY Heatmaps – Updated Version

Mat has updated the DIY Heatmaps for EMC CLARiiON and VNX arrays to version 3.0211. You can get it from the Utilities page here. Any and all feedback welcome. Changes below:

Add –min_colour, –mid_colour, –max_colour options (just a change of spelling of colour)

Remove case sensitivity for colours

Added FC SSD drive type

EMC – DIY Heatmaps – Updated Version

Mat has updated the DIY Heatmaps for EMC CLARiiON and VNX arrays to version 3.021. You can get it from the Utilities page here. Any and all feedback welcome. Changes below:

Add command line options:


–min_color –mid_color –max_color

To allow the user to select different color schemes for their heatmap graphs. The available colors to choose from are (red, green, blue, yellow, cyan, magenta, purple, orange, black, white)



Change the granularity of the heatmap steps, for example on an attribute like % Utilization, if steps is set to 20, there will be different color bands for 0-4%, 5-9%, 10-14%,etc the default is 10 so color bands will be at 0-9%,10-19%,20-29%, etc



This option will allow you to display detail heat graph for an object over time when it has been selected. For example, selecting the SP-B heatmap object below, produces a heat graph for that object over the duration of the NAR file.  Thanks to Ian  for the idea and code behind this.

There have been some other script improvements that:

Add exit code checking after running naviseccli

Browser compatibility fixes – mainly with Chrome, but this should improve display consistency across different browser platforms

EMC – DIY Heatmaps – Updated Version

Mat has updated the DIY Heatmaps for EMC CLARiiON and VNX arrays to version 3.020. You can get it from the Utilities page here. Any and all feedback welcome.