Yellow Bricks

by Duncan Epping

Various

VMkernel Observations (VOBs)

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I never really looked at VOBs but as this came up last week during a customer meeting I decided to look in to it a bit. I hadn’t realized there was such a large number of them in the first place. My conversation was in the context of vSAN, but there are many different VOBs. For those who don’t know VOBs are system events. These events are logged and you can create different alarms for when they are being logged.

You can check the full list of VOBs on ESXi, SSH in to it and then look at this file:

  • /usr/lib/vmware/hostd/extensions/hostdiag/locale/en/event.vmsg

When they are triggered you will see them here:

  •  /var/log/vobd.log

And as stated when you want to do something with them you can create a customer alarm. Select “specific event occuring on this object” and click next:

Now you add an event, simply click the “+” and remove the current value and simply copy/paste the VOB string in, the string will look something like this: “esx.problem.vob.vsan.pdl.offline”. Hit enter when you added it and then click “Next” and “Finish”.

I find the following useful myself:

  • esx.problem.vsan.net.redundancy.reduced
  • esx.problem.vob.vsan.lsom.componentthreshold
  • esx.problem.vob.vsan.lsom.diskerror
  • esx.problem.vob.vsan.pdl.offline
  • esx.problem.vsan.lsom.congestionthreshold
  • esx.problem.vob.vsan.dom.nospaceduringresync

There are many more, and I just listed those I found useful for vSAN, for more detail check the following links:

 

VMworld 2017 is around the corner, which sessions should you attend? My tips!

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Every year I go over “all” accepted VMworld sessions which are publicly listed and provide my top 15 / 20 / 25 / 30 list of VMworld sessions. (Some sessions won’t be revealed until the day before as they could be on the topic of certain announcements) I have had comments in the past around my selection and I hope it is clear that this is my opinion based on the subject and speaker. In some cases they may be familiar names like Cormac Hogan, in some cases it may be a less known person which I’ve seen presenting in the past. I am looking for mostly deep technical sessions, or sessions which I know will simply be enjoyable to attend. Considering there are only a couple of weeks between VMworld US and EMEA I will only do a single post this time. Some sessions may not be accepted for EMEA unfortunately.

Here we go, my top 15 sessions!

  1. VMware CTO Innovation Panel: What’s Next? [FUT3025PU] with Ray O’Farrell, Christos Karamanolis, Chris Wolf, Shawn Bass and Mike Wookey
    I always enjoy panel sessions, and when there’s one with our CTOs it is definitely worth attending. I hope there will be some nice hints in this session of what to expect from VMware in the upcoming years and some good discussion around which directions the industry is heading towards.
  2. Storage at Memory Speed: Finally, Nonvolatile Memory Is Here [FUT3040BU] by Rajesh Venkatasubramanian and Richard Brunner
    NVM is going to change the world of memory and storage, if you want to be prepared for the future then make sure to register. I’ve seen Rajesh present a couple of times and there’s always something to learn, haven’t had the pleasure of seeing Richard live yet, but that is about to change!
  3. vSphere 6.5 Host Resources Deep Dive: Part 2 [SER1872BU] by Frank Denneman and Niels Hagoort
    The book was thorough, deep… extremely deep, and both are excellents presenters. So this session has to be on the list. If you want to know more about NUMA, overlays etc then this is a must.
  4. Migrate to the vCenter Server Appliance You Should [SER2958BU] by William Lam and Emad Younis
    I am big fan of the vCenter Server Appliance, and anytime you can learn how to migrate from the Windows version to the appliance you should. Plus, William and Emad are great speakers!
  5. vSAN 6.6: A Day in the Life of an I/O [STO1926BU] by John Nicholson and Pete Koehler
    Considering all the changes in vSAN and considering the speakers this is a must attend for everyone interested in what the IO path for vSAN looks like. Are you using Dedupe/Compresssion, RAID-1 or RAID-5 or maybe even Encryption? John and Pete will explain what the IO path will look like!
  6. The Power Hour: vSphere PowerCLI 10th Birthday Edition [SER1875BU] by Luc Dekens and Alan Renouf
    The dynamic duo of PowerCLI. I will let it up to you guys to decide who is Batman and who is Robin though. I think I have seen a dozen sessions by these guys and they never disappoint. Usually a large number of demoes and a level of detail that you don’t see often.
  7. Virtual Volumes Technical Deep Dive [STO2446BU] by Patrick Dirks and Pete Flecha
    I have attended various sessions by Pete and Patrick and they were excellent every single time. Patrick is a senior manager in R&D managing the VVol development team, so if you have any in-depth questions… bring them!
  8. vCenter Performance Deep Dive [SER1504BU] by Ravi Soundararajan and Priya Sethuraman
    This was by far the best session at VMworld last year, do I need to say more?
  9. VMware Cloud on AWS: Storage Deep Dive [STO1890BU] by Ben Meadowcroft and Matthew Amdur
    Very interesting topic, Ben is the PM and Matt the lead engineer, so I expect it to be deep!
  10. vSAN Management Today and in the Future [STO1378BU] by JunChi Zhang and Christian Dickmann
    Last year Christian had various tech previews that showed the potential future of vSAN. I think every single demo became reality in the 2 releases that followed. So if you want to know where we stand today and where we will be in the future with vSAN then make sure to attend this one!
  11. VMware Cloud on AWS: A Technical Deep Dive [LHC2384BU] by Frank Denneman and Ray Budavari
    Interesting topic, haven’t heard too much (in-depth) on VMware Cloud on AWS so this would be a great session to dive deep and get more familiar with the offering and the architecture behind it!
  12. A Deep Dive into vSphere 6.5 Core Storage Features and Functionality [SER1143BU] by Cody Hosterman and Cormac Hogan
    Probably my two fav storage bloggers. Cody and Cormac jointly wrote a white paper on this topic and have been the go to people for anything on core storage for the past years, and great speakers. You can’t go wrong!
  13. Advanced Troubleshooting of ESXi Server 6.x for vSphere Gurus [SER2965BU] by Ragavendra Kumar and Abhilash Kunhappan
    I don’t know the presenters, but the topic alone makes me want to attend this one…
  14. Extreme Performance Series – ALL
    Not listing a specific session in this case, the performance team has many sessions, just search for “extreme performance series” and they will pop-up. They will all be deep, and most likely very educational.
  15. Sustainability as a Competitive Advantage [FUT2051BU] by Rob Glanzman and Nicola Acutt
    This is the odd one in the mix. Not a deepdive, and I don’t even think it is a technical session. I know Rob and Nicola well though, and I know what Nicola has been working on and this session caught my attention as it is something different for a change. How can you get a competitive edge through sustainability?

And for those who care, here are my own two sessions:

vSAN 6.6 available now

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vSAN 6.6 is available now. Check the release notes before you upgrade! Also note that for vSAN users currently on 6.0 Update 3 – upgrade to vSAN 6.6 is not yet supported. If you like to learn more about vSAN 6.6 check the following material:

Note that vSAN 6.6 comes as a patch release, download the bits here from the vSAN 6.6 landing page:

 

Virtually Speaking Podcast episode 32 – VVol 2.0

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Just wanted to share the Virtually Speaking Podcast with you, this episode (32) is on the topic of VVol 2.0 and features Pete Flecha, Ben Meadowcroft (PM for VVol) and I. Make sure to listen to it, it has some good info on where VVol is today and where it may be going in the near future!

The difference between VM Encryption in vSphere 6.5 and vSAN encryption

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More and more people are starting to ask me what the difference is between VMCrypt aka VM Encryption and the beta feature we announced not to long ago called vSAN Encryption. (Note, we announced a beta, no promises were made around dates or actual releases or releasing of the feature.) Both sounds very much the same and essential both end up encrypting the VM but there is a big difference in terms of how it is implemented. There are advantages and disadvantages to both solutions. Lets look at VM Encryption first.

VM Encryption is implemented through VAIO (vSphere APIs for IO Filters). The VAIO framework allows a filter driver to do “things” to/with the IO that a VM sends down to a device. One of these things is encryption. Now before I continue, take a look at this picture of where the filter driver sits.

As you can see the filter driver is implemented in the User World and the action against the IO is taken at the top level. If this for instance is encryption then any data send across the wire is already encrypted. Great in terms of security of course. And all of this can be enabled through policy. Simply create the policy, select the VM or VMDK you want to encrypt and there you go. So if it is that awesome, why vSAN Encryption?

Well the problem is that all IO is encrypted at the top level. This means that it is received in the vSAN write buffer fully encrypted, then the data at some point needs to be destaged and is deduplicated and compressed (in all-flash). As you can imagine, encrypted blocks do not dedupe (or compress) well. As such in an all-flash environment with deduplication and compression enabled any VM that has VM Encryption through VAIO enabled will not provide any space savings.

With vSAN Encryption this will be different. The way it will work is that it will provide “encryption at rest”. The data travels to the destination unencrypted then when it reaches its destination it is written encrypted to the cache tier, then it is decrypted before it is destaged, and it will be encrypted after it is deduplicated and/or compressed again. This means that you will benefit from space saving functionality, however encryption in this case is a cluster wide option, which means that every VM will be encrypted, which may not be desirable.

So in short:

  • VM Encryption (VAIO)
    • Policy based (enable per VM)
    • Data travels encrypted
    • No/near zero dedupe
  • vSAN Encryption
    • Enabled on a cluster level
    • Data travels unencrypted, but it is written encrypted to the cache layer
    • Full compatibility with vSAN data services

I hope that clarifies why we announced the beta of vSAN Encryption and what the difference is with VM Encryption that is part of vSphere 6.5.