We had some technical difficulties with Matt getting on the podcast so, Ray had to fly solo. This month we continue our investigations into K8s storage with a discussion with Tad Lebeck (@TadLebeck) US CTO, ionir, a software defined storage system that only runs under K8s. ionir Kubernetes Data Services platform is an outgrowth of Reduxio a “tin-wrapped” software defined storage system which pivoted to K8s as the environment to target and left the tin behind.
ionir offers a deduplicating, continuous data protection storage system for PVs (persistent volumes) under K8s that uses 3 way mirroring, across data nodes for data protection. Their solution offers a number of unique services that we haven’t seen in other K8s storage systems. Listen to the podcast to learn more.
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Tad opened with a long spiel on what ionir is and we spent the next 40 minutes unpacking that to understand what exactly they were doing.
Let’s start with why stateful containers are all the rage these days. Tad had a slightly different rationale than we’ve heard before. From his perspective, it all comes from current enterprise applications that used database servers/machines. As these apps are re-factored to run as K8s containerized micro services, developers need and want their data be containerized right along with the application.
ionir constructs a block storage system across K8s data nodes or K8s worker nodes with direct attached storage. In the cloud, this storage can be ephemeral (storage that only exists as long as the compute instance operates) or normal block storage (e.g., EBS in AWS). It’s unclear how ephemeral works on-prem. But in any case, they cluster together a set of data nodes into one massive block storage and map PVs onto that. K8s data nodes can be added to the ionir cluster while it’s operating.
As mentioned earlier, they use 3-way mirroring for data protection and ionir insures the 3 copies are stored on different data nodes. As such, when one data node goes down, copies of PV data are available from the other 2 nodes and the data can then be rewritten elsewhere to insure 3-way mirroring continues. We suppose this means a minimum configuration requires at least 3 data nodes.
ionir also provides deduplicating block storage, which should theoretically reduce physical storage footprint for any PV. Data blocks are deduplicated across the cluster. ionir also has a metadata service (also 3 way replicated, to different data space) that records the manifest for all blocks associated with a PV, their hashes and (logical/physical) locations.
There was no mention of data compression or encryption so those are probably not present. We find deduplication very effective for backup storage but less effective for primary storage. Any deduplication ratio for ionir primary storage is likely specific to data being stored, i.e. columnar database, row database, text, office files, etc. Each of these would likely have different dedupe ratios for primary storage.
Furthermore, ionir supplies continuous data protection (CDP) for PV data. PV data written to ionir is immutable, i.e., never modified AND they keep previous versions of PV blocks in storage until they age out. This allows ionir to provide any prior version (well most recent ones) of a PV. ionic uses a timestamp to distinguish different PV versions. So, if ransomware attacked your site, users could ask for a PV version just prior to the time of the attack and you’d have that version of the PV to restart operations. Customer’s can limit how far back ionir saves prior versions of blocks for PVs.
Having CDP for PVs, makes DevOps qualification and testing significantly faster. Normally DevOps would need to copy production data to test environments in order to validate new app code. But ionir can easily instantiate a separate copy of any PV (at any time in their saved set) in a matter of seconds. This can take DevOps deployment testing down from days to minutes or less.
In addition, ionir can teleport PV data to other, remote K8s clusters running ionir. Essentially, this copies PV metadata and it’s “hot” blocks over to any remote ionir cluster. During teleportation, the remote cluster can access PV data as soon as all PV metadata has been copied. The remote site accesses this PV data from the originating cluster (albeit much slower than accesses within the cluster) while “hot” blocks are being copied. Any writes, at the remote site, to PV data would be considered new data, deduplicated at the remote site, and only available at the remote site. Somewhat surprisingly, all of the PV’s data is never copied to the remote system, leaving the PV in a permanent teleported access mode.
Not sure we like the implications of teleporting PVs, from a data integrity perspective. It does make for near-instant access to PV data from other clusters and offers a solution to data gravity (it takes forever to move TB of data across the web), it’s incomplete, as the data is never fully copied to the remote site. Once hot blocks have been copied, remote cluster PV access should run faster. But If there’s 20% of the requested blocks, not in the heat map, those IOs will take 100s mseclonger, depending on wire distance between the sites, to perform. And the write’s at the remote site cause the two copies (one at source site and one at remote site) of the PV to diverge.
Their storage system is priced on a per data node basis which makes it easy to price out their various deployment options. And it works on any K8s standard environment, although Tad admits they haven’t tested VMware Tanzu yet, but they have tested it on GCP, Microsoft Azure, AWS, and Red Hat OpenShift.
They offer a fully functional free trial of ionir storage, only capped at the number of data nodes in use. So, if you only need a small amount of storage (ok 3 data nodes with 24 14TB SSDs each make for large amount of storage) for your K8s environment, you can probably run forever on the free version.
Tad Lebeck, US CTO, ionir
Tad Lebeck is a global technology executive with over two decades of experience in startups and large vendors. Prior to ionir, he founded and led Nuvoloso, an innovator in Kubernetes data services. Earlier, Lebeck served as CTO at Huawei Symantec Technologies, Vice President at Symantec/Veritas, co-founder/CTO at Invio, and CTO at Legato Systems, where he helped create the modern enterprise data-protection market.
Tad was a founding member of the SNIA Technical Council. He earned an MS/CS from the University of Wisconsin, and a combined MBA from the Columbia, London, and HKU Schools of Business.