Hybrid Cloud for z

September 27th, 2017

Ian Wright
Client Technical Sales Engineer


Hybrid Cloud is a challenging topic from any angle. On one hand, our customers want to take advantage of the flexibility and scale that Cloud offers. On the other hand, they already have an existing infrastructure, and trying to make the two play together introduces some complexity. But done right, the hybrid cloud goal could allow enterprise datacenters to reduce their storage spend, while improving flexibility. This could be done by keeping only the data that’s truly relevant and needed on expensive local storage, while sending off older data to the cheaper and more flexible systems or providers.

To help simplify the use of cloud with existing storage infrastructures, IBM has introduced the concept of “Transparent Cloud Tiering” on three of its premier storage platforms…the DS8000, Spectrum Scale, and Spectrum Virtualize. In this post, we’ll focus on the DS8000 version.

Before getting into the specifics, let’s restate the fact of cloud. It’s just a computer or storage, which is managed in a different way, and possibly (but not definitely), by someone else. In these cases, the cloud could be a Cloud Service Provider (CSP), an S3 or OpenStack Swift container, which could be provided by IBM Cloud Object Storage, Red Hat Ceph with OpenStack, or anything else. With the DS8000, the cloud could even be an IBM TS7700 Tape System!

Specifically, this is going to address mainframe cloud storage. Yes, that mainframe which is always going to disappear and be replaced. As usual, it’s doing well and keeping itself relevant.

In the case of TCT for the DS8000, it’s taking advantage of code that’s been around since the dawn of time (as is so often the case with the mainframe) and repurposing it. In this event, that code is DFSMShsm (hierarchical storage management). The capability is available with limited function on the DS8870 (only to Swift), but the DS8880 8.2.3 has much richer function and relies on zOS 2.2.

While hsm has always been able to migrate cold data sets to tape, it is an IO intensive process. Particularly as datasets get larger, the IOPS impact grows considerably. Additionally, there is work constantly being done in typical tape implementations, as data is recycled. With TCT, hsm doesn’t have the same amount of overhead. Instead of worrying about allocating tapes, blocking the data, and synchronizing, hsm now has a “cloud” Storage Tier. With it, the hsm will “put” a dataset into an object store (yes, even if it’s on tape) directly from the ethernet ports on the DS8000. If datasets end up being needed in the future, it will recall them the same way.

For mainframe customers, however, this is probably not enough. Security is top of mind for our customers right now, especially after the recent hacks involving Equifax, the SEC, Deloitte, and CCleaner. To that, the DS8000 version of TCT has incorporated System z security, which includes System z audit logging, RACF, and Top Secret. Additionally, the data is encrypted in flight, so the data is protected from any packet sniffing or other means of scanning the data.

By removing cold storage from a production DS8880, one could easily see having a small, but all-Flash DS8880, and keeping the cold data in Object Stores.

As I mentioned earlier, this could even be an IBM tape system. Specifically, the TS7700s can be set up to act as object stores (rather than as tape volumes) and receive information from the DS8880 ethernet ports. Meanwhile the DS8880 is set up to be, effectively, part of the GRID. This results in the advantages of tape, in terms of its power efficiency and cost, but significantly less IOPS while also eliminating the “recycle” process that is typically associated with hsm moving data to tape

It’s important to note that this use of the TS7700 is still early and not for production just yet, but it gives a great indication of how System z storage will be handled going forward.

Hybrid Cloud represents a great opportunity for our customers, and we look forward to any opportunity to discuss how we can help maximize its value on all platforms.

In the next episode of this blog, I’ll address the open systems capable versions of TCT for Spectrum Scale and Spectrum Virtualize.

Feel free to call your Mainline SE or Account Executive to ask about Transparent Cloud Tiering, or contact us with questions on any other IT needs you may have.

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