Yellow Bricks

by Duncan Epping

vvol

SRM support for VVols coming!

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VMworld is coming up, which means that is “announcements season”. First announcement that I can share with you is the fact that VVols support for SRM is now officially on the roadmap. This is something Cormac and I have pushed hard for the past couple of years, and it is great to see this is finally being planned! A post about this was just published on the VMware Virtual Blocks blog and I think the following piece says it all. Read the blog for more info.

Some of our storage partners such as HP Enterprise 3PAR, HP Enterprise Nimble, and Pure Storage have developed and certified to the lastest VVol 2.0 VASA providers specification. VVol 2.0 is part of the vSphere 6.5 release and supports array-based replication with VVol.  To support VVol replication operations on these storage arrays, VMware also developed a set of PowerCLI cmdlets so common BC/DR operations such as failover, test failover, and recovery workflows can be scripted as needed. The use of PowerCLI works well for many VVol customers, but we believe many more customers will be able to take advantage of SRM orchestrated BC/DR workflows with VVol.

I can’t wait for this to be made available, and I am sure many VVol customers (and potential customers) will agree with me that this is a highly anticipated feature!

VVols design and procurement considerations

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Over the past couple of months I have had more and more discussions with customers and partners about VVols. It seems that Policy Based Management and the VVol granular capabilities are really starting to sink in, and more and more customers are starting to see the benefit of using vSphere as the management plane. The other option of course is pre-defining what is enabled on a datastore/LUN level and use spreadsheets and complex naming schemes to determine where a VM should land, far from optimal. I am not going to discuss the VVols basics at this point, if you need to know more about that simply do a search on VVol.

When having these discussions a bunch of things typically come up, these all have to do with design and procurement considerations when it comes to VVol capable storage. VMware provided a framework, and API, and based on this each vendor has developed their own implementation. These vary from vendor to vendor, as not all storage systems are created equal. So what do you have to think about when designing a VVols environment or when you are procuring new VVol capable storage? Below you find a list of questions to ask, with a short explanation of why this may be important. I will try to add new questions and considerations when I come up with them.

  • What level of software is needed for my storage system to support VVol?

In many cases, especially existing legacy storage systems, an upgrade is needed of the software to support VVols, ask:

  • What does this upgrade entail?
  • What is the risk?

When it is clear what you need to support VVols from a software point of view, ask:

  • What are the constraints and limits?
    • How many Protocol Endpoints can I have per storage system?
      • Do you support all protocols? (FC, NFS, iSCSI etc)
      • Is the IO proxied via the Protocol Endpoint? If it is, is their an impact with a large number of VMs?
        • Some systems can make a distinction between traffic type and for normal IO will not go through the PE, which means you don’t hit any PE limitations (queue depth being one)
    • How many Storage Pools can you have per storage system?
      • In some cases (legacy storage systems) the storage pool equals an existing physical construct on the array, what is it and what is the impact of this?
        • What kind of options do I select during the creation of the pool? Anything you select on a per Pool level means that when you change policy VVols may have to migrate to other pools, I prefer to avoid data movement. In some cases for instance “replication” is enabled on a storage pool level, I prefer to have this as a policy option
    • How many VVols can I have per storage system? (How many VMs do you have, and how many VVols do you expect to have per VM?)
      • In some cases, usually legacy storage systems, the number of VVols per array is limited. I have seen as “low” as 2000, with 3 VVols per VM at a mininum (typical 5) you can imagine this restricts the number of VMs you can run on single storage system

And then there is the control / management plane:

  • How is the VASA (vSphere APIs for Storage Awareness) Provider implemented?
    • There are two options here, either it comes as part of the storage system or it is provided as a virtual machine.
  • Then as part of that there’s also the decision around the availability model of the VASA Provider:
    • Is it a single instance?
    • Active/Standby?
    • Active/Active?
    • Scale-out?

Note, as it stands today, in order to power-on a VM or create a VM the VASA Provider needs to be available. Hence the availability model is probably of importance, depending on the type of environment you are designing. Also, some prefer to avoid having it implemented on the storage system, as any update means touching the storage system. Others prefer to have it as part of the storage system as it removes the need to have a separate VM that needs to be managed and maintained.

Last but not least, policy capabilities:

  • What is exposed through policy?
    • Availability? (RAID type / number of copies of object)
    •  QoS?
      • Reservations
      • Limits
    • Replication?
    • Snapshot (scheduling)?
    • Encryption?
    • Application type?
    • Thin provisioning?

I hope this helps having the conversation with your storage vendor, developing your design or guide the conversation during the procurement process. If anyone has additional considerations please leave a comment so I can add it to the list when applicable.

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!

vSphere 6.5 what’s new – VVols

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Well I guess I can keep this one short, what is new for VVols? Replication. Yes, that is right… finally if you ask me. This is something I know many of my customers have been waiting for. I’ve seen various customers deploy VVols in production, but many were holding off because of the lack of support for Replication and with vSphere 6.5 that has just been introduced. Note that alongside with new VVol capabilities we have also introduced VASA 3.0. VASA 3.0 provides Policy Components in the SPBM UI which allows you to combine for instance a VVol policy with a VAIO Filter based solution like VMCrypt / Encryption or for instance Replication or Caching from a third party vendor.

When it comes to replication I think it is good to know that there will be Day 0 support from both Nimble and HPE 3PAR. More vendors can be expected soon. Not only is replication per object supported, but also replication groups. Replication groups can be viewed as consistency groups, but also a unit of granularity for failover. By default each VM will be in its own replication group, but if you need some form of consistency or would like a group of VMs always to failover at the same time then they can be lumped together through using the replication group option.

There is a full set of APIs available by the way, and I would expect most storage vendors to provide some tooling around their specific implementation. Note that through the API you will for instance be able to “failover” or do a “test failover” and even reverse replication if and when desired. Also, this release will come with a set of new PowerCLI cmdlets which will also allow you to failover and reverse replication, I can’t remember having seen the test failover cmdlet but as it is also possible through the API that should not be rocket science for those who need this functionality. Soon I will have some more stuff to share with regards to scripting DR scenarios…

Goodbye SAN Huggers!

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This week I presented at the German VMUG and a day after the event someone commented on my session. Well not really on my session, but more on my title. My title was “Goodbye SAN Huggers“. Mildly provocative indeed. “SAN Huggers” is a play on the term “Server Hugger“. That term has been around for the longest time and refers to people who prefer to be able to point out their servers. People who prefer the physical world, where every application ran on one server and every server was equal to one physical box.

SAN Huggers are pretty much the same type of people. They prefer the physical world. A world where they define RAID Groups, Storage Pools and LUNs. A world where a bunch of servers end up on the LUN they created. Those LUNs have certain data services enabled and if you need other data services, well then you simply move your servers around! SAN Huggers like to maintain strict control, and to me personally they are in the same position the Server Huggers were 12-15 years ago. It is time to let go however!

Now let it be clear, 12-15 years ago when virtualization changed the world of IT and VMware exploded literally and server huggers felt threatened by the rise of virtualization servers did not go away. Server Administrators did not disappear. Server Administrators evolved. Many took on additional responsibilities, in most cases that would be the responsibility over VMware ESX / Virtual Infrastructure. The same applies to storage.

When I say goodbye SAN Huggers, I am not referring to “Virtual SAN” taking over the world. (Although I do think that Hyper-Converged will eat the traditional storage system’s lunch for a large portion.) I am talking about how the world of storage is (and has been) evolving. Literally my next slide typically has a quote on it that states the following: “Hardware evolution started the storage revolution“. The story around this slide makes it clear what I mean when I say Goodbye SAN Huggers.

The hardware evolution has literally changed the storage landscape. Software Defined Storage is quickly taking over the world, but in my opinion the key reason for this is the evolution from a hardware perspective. In the past we had to group harddisk to provide a single unit that could deliver sufficient capacity, performance and increase availability at the same time. That was achieved using RAID constructs, and with the introduction of virtualization and high demanding workloads storage systems had to resort to wide striping, introduced larger caches, disk pools etc to deliver the capabilities required.

In todays world a lot of these constructs are no longer needed. The evolution in the world of hardware allowed for the introduction of Software Defined Storage. First and foremost flash, whether PCIe, NVMe or SAS/SATA based. These devices removed the need for complex constructs to provide thousands of IOPS. A single flash device today, even consumer grade, can provide higher performance than many of the storage systems we have all managed over the years. Not even talking about enterprise grade flash devices where 100k IOPS (with sub millisecond latency) is more or less the norm. Than there is the network, 10GbE, 25GbeE, 40GbE and even higher. Low latency and high bandwidth comes at (relative) low cost, and add to that the ever growing CPU capabilities, cores and speed combined with faster bus speeds and high (and fast) memory configurations. Hardware is no longer a constraint, the revolution is now, enter the world of Software Defined Storage.

And this, this is where I typically introduce: Virtual SAN, Virtual Volumes and the vSphere APIs for IO Filtering (vSphere Data Services delivered through filter drivers). Functionality provided by VMware which enables efficient operations, simplicity and flexibility. All through the use of policy, which can simply be attached to your workloads, be it a virtual machine or virtual disk even. The days of creating LUNs, RAID groups and needing wide striping or huge amounts of devices to get a decent user experience are gone. We can say goodbye to the physical world, we can say goodbye to the SAN Hugger. We can move forward and evolve, not just our datacenters but also our personal growth and areas of interest and expertise as a result.