If you are using Hitachi HAM (High Availability Manager) with HUS VM I would like to ask you to read this.

The post is about an issue/impact we have noticed and that we were able to reproduce in a lab environment.

So I would be interested if you as HAM/HUS VM customer have already noticed this issue, too and – if yes – can provide me feedback (eg. via Twitter @lessi001 or in the comments).

Interested? Here are the details:

Issue description/impacts:

If you are using HDS HAM with HUS VM, there are tasks where you have to do storage path manipulation using a HDS tool called „HGLM“ (Hitachi Global Link Manager), eg. to perform a failback after a storage failover or in a planned failover/failback scenario.

After manipulating a higher number of paths (eg. setting more than 50 paths per host to off or active) we notice the following impacts:

  • ESXi host becomes unresponsive
  • performance logs are not longer recorded
  • up to 100 percent CPU load on ESXi host

These impacts can last from one minute up to three hours – depending on the number of paths, load of the ESXi host and likely the condition of the storage system.


Cause of this behaviour:

HDS HGLM is using the „esxcli storage core path set“ command for the path manipulation.  Unfortunately, this command triggers a datastore rescan every time when executed.

The rescan is necessary as the command changes the topology of the host storage, and the rescan brings the storage data in hostd/vCenter up to date (info from VMware support/engineering)

So if you manipulate eg. 300 paths, the command triggers 300 storage rescans, too!

And this leads to the impacts as described above, as the hostd cannot deal with this high rate.

In our reproduction scenario we tried the same path manipulation with the „localcli“ command. This command does not trigger a rescan in hostd and that’s why the issue is not exposed by „localcli“.

I need your feedback:

If you are a HAM/HUS VM customer and have already noticed these impacts – please get in touch with me (Twitter @lessi001 or via the comments).

If you are a HAM/HUS VM customer and want to know if you have the same issue, you can try to reproduce it in your lab environment. Just catch up with me and I can tell you what we’ve tried.

You want to go to VMworld 2015 US or Europe, but your company/boss does not want to pay for the conference pass?

Then try your luck and win your pass to the show in one of the many sweepstakes.

In this post I try to put together a list with possibilities where and how you can win tickets for VMworld 2015 US and Europe. If one is missing – leave a comment or write me a DM via Twitter @lessi001.

vmturbo_winVMTurbo VMworld 2015 Sweepstakes

VMTurbo raffles full conference passes – there are three drawings: May 29,  June 19  and July 10. Register here to win!



evorail_logoEVO:RAIL Hands-on Lab Challenge

Between May 1, 2015 and August 20, 2015 you can win a full conference pass in the EVO:RAIL Hands-on Lab Challenge:

Each month, VMware will announce the winners:

The three best scores (minimum time to complete the lab) will receive a 2015 full conference pass to their choice of VMworld San Francisco or VMworld Barcelona! Interested?

Try your luck here: EVO:RAIL Hands-on Lab Challenge

BusinessMobilityBusiness Mobility Summit (16. june 2015)

Join the Business Moblility Summit and win a VMworld pass from CloudCredibility.com.

Read more about the event and register here: VMware Business Mobility Summit

Only 15 weeks left until VMworld 2015 US will take place in San Francisco. So it is time to register to benefit from the early bird discount!

The early bird price is only applicable until June 9th – and it will save you 300 bucks!

Registration for VMworld US (October 12-15, 2015) is already open: VMworld 2015 Registration

Some other important dates:

  • Content Catalog will go live June 9th
  • Schedule Builder will go live July 21


VMworld 2015 Europe (Barcelona):

If you plan to attend VMworld 2015 Europe, these dates may be of interest for you:

The conference will take place from October 12-15, 2015 in Barcelona, as in the last two years. Registration for the EMEA Conference will open June 9th.

Content Catalog will go live June 23 and the schedule builder is expected to go live August 18th.

To register for the conference use this link: VMworld 2015 Registration

Sometimes, during backup the following error occurs on an individual virtual machine:

An error occurred while saving the snapshot: msg.snapshot.error-QUIESCINGERROR.


If you have already tried other workarounds to perform the backup successfully, the only last chance is to remove the VSS component on this dedicated VM.

Other workarounds you can try are:

How to remove the VSS component:

  • right-click the VM and select „Guest“ – „Install/Upgrade VMware Tools“
  • select „Interactive Tools Upgrade“
  • log-on to the virtual machine and start the VMware Tools Setup (you can start it via Explorer – DVD Drive)
  • select „Custom“:
  • deselect the „VSS Support“ (Volume Shadow Copy Service Support)
  • now finish the wizzard – done!

If possible reboot the virtual machine. Backup should work without a reboot, too – but it is recommended…