Dell EMC VxRail 4.5 – A Few Notes

VxRail 4.5 was announced in May by Dell EMC and I’ve been a bit slow in going through my enablement on the platform. The key benefit (beyond some interesting hardware permutations that were announced), is support for VMware vSphere 6.5 U1 and vSAN 6.6. I thought I’d cover a few of the more interesting aspects of the VxRail platform and core VMware enhancements.

Note that VxRail 4.5 does not support Generation 1 hardware, but it does support G2 and 3 Quanta models, and G3 Dell PowerEdge appliances.

 

VxRail Enhancements

Multi-node Additions

Prior to version 4.5, adding an additional node to the existing cluster was a bit of a pain. Only one node could be added at a time and this could take some time when you had a lot of nodes to add. Now, however,

  • Multiple nodes (up to 6) can be added simultaneously.
  • Each node expansion is a separate process. If one fails, the remaining five will keep going.

There is now also a node removal procedure, used to decommission old generation VxRail products and migrate to new generation VxRail hardware. This is only supported for VxRail 4.0.301 and above and removal of only one node at a time is recommended.

 

Network Planning

Different VLANs are recommended for vSAN traffic and for management across multiple VxRail clusters.

 

VxRail network topologies use dual top-of-rack (ToR) switches to remove the switch as a single point of failure.

 

vSAN 6.6 Enhancements

Disk Format 5

As I mentioned earlier, VxRail 4.5 introduces support for vSAN 6.6 and disk format 5.

  • All nodes in the VxRail cluster must be running vSAN 6.6 due to the upgraded disk format.
  • The upgrade from disk format 3 to 5 is a metadata only conversion and data evacuation is not required. You need disk format 5 is required for datastore-level encryption (see below).
  • VxRail will automatically upgrade the disk format version to 5 when you upgrade to VxRail 4.5.

 

Unicast Support

Unicast is supported for vSAN communications starting with vSAN 6.6. The idea is to reduce network configuration complexity. There is apparently no performance impact associated with the use of Unicast. vSAN will switch to unicast mode once all hosts in the cluster have been upgraded to vSAN 6.6 and disk format 5. You won’t need to reconfigure the ToR switches to disable multicast features in vSAN.

 

vSAN Data-at-Rest Encryption

vSAN Data-at-Rest Encryption (D@RE) is enabled at cluster level, supporting hybrid, all-flash, and stretched clusters. Note that it requires an external vCenter and does not support embedded vCenter. It

  • Works with all vSAN features, including deduplication and compression.
  • Integrates with all KMIP-compliant key management technologies, including SafeNet, HyTrust, Thales, Vormetric, etc.

When enabling encryption, vSAN performs a rolling reformat of every disk group in the cluster. As such, it is recommended to enable encryption on the vSAN datastore after the initial VxRail deployment. Whilst it’s a matter of ticking a checkbox, it can take a lot of time to complete depending on how much data needs to be migrated about the place.

 

Other Reading

You can read more about vSAN D@RE here. Chad delivered a very useful overview of the VxRail and VxRack updates announced at Dell EMC World 2017 that you can read here.

EMC Announces VxRail

Yes, yes, I know it was a little while ago now. I’ve been occupied by other things and wanted to let the dust settle on the announcement before I covered it off here. And it was really a VCE announcement. But anyway. I’ve been doing work internally around all things hyperconverged and, as I work for a big EMC partner, people have been asking me about VxRail. So I thought I’d cover some of the more interesting bits.

So, let’s start with the reasonably useful summary links:

  • The VxRail datasheet (PDF) is here;
  • The VCE landing page for VxRail is here;
  • Chad’s take (worth the read!) can be found here; and
  • Simon from El Reg did a write-up here.

 

So what is it?

Well it’s a re-envisioning of VMware’s EVO:RAIL hyperconverged infrastructure in a way. But it’s a bit better than that, a bit more flexible, and potentially more cost effective. Here’s a box shot, because it’s what you want to see.

VxRail_002

Basically it’s a 2RU appliance housing 4 nodes. You can scale these nodes out in increments as required. There’s a range of hybrid configurations available.

VxRail_006

As well as some all flash versions.

VxRail_007

By default the initial configuration must be fully populated with 4 nodes, with the ability to scale up to 64 nodes (with qualification from VCE). Here are a few other notes on clusters:

  • You can’t mix All Flash and Hybrid nodes in the same cluster (this messes up performance);
  • All nodes within the cluster must have the same license type (Full License or BYO/ELA); and
  • First generation VSPEX BLUE appliances can be used in the same cluster with second generation appliances but EVC must be set to align with the G1 appliances for the whole cluster.

 

On VMware Virtual SAN

I haven’t used VSAN/Virtual SAN enough in production to have really firm opinions on it, but I’ve always enjoyed tracking its progress in the marketplace. VMware claim that the use of Virtual SAN over other approaches has the following advantages:

  • No need to install Virtual Storage Appliances (VSA);
  • CPU utilization <10%;
  • No reserved memory required;
  • Provides the shortest path for I/O; and
  • Seamlessly handles VM migrations.

If that sounds a bit like some marketing stuff, it sort of is. But that doesn’t mean they’re necessarily wrong either. VMware state that the placement of Virtual SAN directly in the hypervisor kernel allows it to “be fast, highly efficient, and be able to scale with flash and modern CPU architectures”.

While I can’t comment on this one way or another, I’d like to point out that this appliance is really a VMware play. The focus here is on the benefit of using an established hypervisor (vSphere), and established management solution (vCenter) and a (soon-to-be) established software defined storage solution (Virtual SAN). If you’re looking for the flexibility of multiple hypervisors or incorporating other storage solutions this really isn’t for you.

 

Further Reading and Final Thoughts

Enrico has a good write-up on El Reg about Virtual SAN 6.2 that I think is worth a look. You might also be keen to try something that’s NSX-ready. This is as close as you’ll get to that (although I can’t comment on the reality of one of those configurations). You’ve probably noticed there have been a tonne of pissing matches on the Twitters recently between VMware and Nutanix about their HCI offerings and the relative merits (or lack thereof) of their respective architectures. I’m not telling you to go one way or another. The HCI market is reasonably young, and I think there’s still plenty of change to come before the market has determined whether this really is the future of data centre infrastructure. In the meantime though, if you’re already slow-dancing with EMC or VCE and get all fluttery when people mention VMware, then the VxRail is worth a look if you’re HCI-curious but looking to stay with your current partner. It may not be for the adventurous amongst you, but you already know where to get your kicks. In any case, have a look at the datasheet and talk to your local EMC and VCE folk to see if this is the right choice for you.