I’m Bringing Flexy Back – NetApp FlexGroup

Back in June 2016 NetApp made a handful of big software development announcements firstly a new naming convention, out went the many operating system variants, CDOT, Clustered ONTAP etc. to be replaced by just ONTAP. ONTAP 9 was announced and in the first weeks of September we saw the General Availability of that source code to the current FAS hardware range as well as the newly rebranded ONTAP Select, ONTAP’s Software Defined Storage version.

Another part of that announcement was a more formal, 6 monthly release cadence and without disappointment NetApp have this week announced ONTAP 9.1.

Three things really stand out in this release in my opinion;

1. New Hardware Platforms – support for more CPU cores, more memory, higher speed Ethernet and fibre channel options.
2. Scalable NAS – NetApp FlexGroup – Something this post will dive into later on.
3. Flexible Encryption – Volume level encryption for standard SSDs and HDDs.

From those announcements the one I’d like to focus on is the newly announced “Massively scalable containers (FlexGroup)”

To explain what NetApp FlexGroups are we should look at what NetApp have today in the form of their Flexible Volumes (FlexVol)

A FlexVol is a storage construct, a container as such, that is owned by a single node within a disk aggregate, that FlexVol can span the entire aggregate and within reason be grown and shrunk accordingly. However, a FlexVol has a limitation of 100TB in total size (this is platform dependent, so can be smaller on some controllers)

A FlexGroup looks to address these specific challenges.

How does it work? Firstly, a volume is still owned by a node and an aggregate. However, these volumes can be pooled together spanning many nodes within the cluster. This aggregating of volumes addresses both of the challenges of a single FLEXVOL. Firstly reads and writes will then span multiple nodes within the cluster. Secondly the ability to pool together up to 200 FlexVols into a single flexGroup means the single storage container limit rockets from 100TB to 20PB.

But does this add complexity to our environment? Thankfully not, simply create those FlexVol containers and let ONTAP do the rest. ONTAP will slice up the FlexGroup into extents of equal size.

Can FlexGroups and FlexVols co-exist? And the answer is absolutely yes. Not all workloads are going to thrive on a FlexGroup so there is still very much a need for Flexible Volumes that we have known and loved for so long.

What about Snapshots? Previously NetApp Snapshots have been created at the FlexVol level so how does this work in a FlexGroup configuration. They are done at the member level meaning they are coordinated across all members.  IO is quiesced briefly to ensure consistency across all FlexGroup volumes.

Aren’t these like infinite volumes?
Good question Clustered ONTAP 8.1.1 introduced “infinite volumes”, now I for one did not see any real life scenarios or compelling use cases for infinite volumes, due to a number of limitations that are now addresses in FlexGroups.

In the table below you can see the differences between these infinite volumes and the newly launched FlexGroups.

As I said above there are certain workloads that will thrive on this sort of NAS based storage container structure but also some that won’t. the key benefits I can see are as follows:

• Single Namespace
• Simplified Administration
• Integrated Storage Efficiency
• Cluster-Wide metadata scaling eliminates single volume bottlenecks
• Tremendous bandwidth for IO heavy workloads.

These benefits I think can be hugely beneficial with the right use case;

• Large repositories for media content
• Healthcare artefacts (not sure what an artefact is though!)
• Compute intensive NAS workloads

And although infinite volumes had offered the capacity for these workloads, they did not deliver that key element of performance, so well addressed in Flexgroups.

The key takeaways for the new NetApp FlexGroup features, is really depending on the workload that fits as mentioned above, the most compelling point though is that these can be used next to those flexible volumes, so you are not having to sacrifice something to gain this new feature.

As I said right at the beginning, there were also other announcements made today from NetApp regarding FAS platforms and also other ONTAP features that are being announced. As and when I get my fellow A-Team members posts and other related posts I will make a point to add them in here.

NetApp revamps their entire FAS and AFF lineup! Read about it here: https://t.co/ONuYRdk488 via @ChrisMaki

Tech conferences mean tech announcements – here’s my take https://techstringy.wordpress.com/2016/09/26/shiny-and-new/ via @techstringy

Read about the biggest release in @NetApp’s history with a revamp of their entire hardware range https://t.co/HNh5ok4VKy via @davebrown1969