Working with LTO? Know your HBA

Decoding the Invisible: The Critical Role of Host Bus Adapters (HBAs) in a Seamless LTO Setup

When people are looking at moving their archive to LTO, most don't realize the amount of moving pieces that makes up a working LTO setup. Besides all the required drivers and frameworks, arguably the most essential yet invisible part of a working LTO setup is the Host Bus Adapter, or HBA.

Parts Unknown

A host bus adapter (or) HBA is a PCIe card that makes it possible to connect a SAS (serial-attached SCSI) device to a computer, directly on the motherboard (with a PC or Mac Pro) or via Thunderbolt for laptops and Macs. HBAs were abundant in a distant era where high-end server hard disks used SAS instead of SATA. Because LTO drives also used to be server-focused, these devices still come equipped with SAS ports. Today, SAS-equipped hard disks have gone the way of the dodo, but LTO obviously hasn't.

In the time of desktop towers like the original Mac Pro it was easy to (physically) see that an LTO drive needed an expansion card to connect it to your computer. But with the advent of desktop Thunderbolt LTO machines some 10 years ago, the visibility of HBAs has been minimized; vendors like Symply, MagStor, and mLogic offer an enclosure that has Thunderbolt on the outside but packs all the in-between bits within its enclosure:

The kicker: only the sole internal bit that is invisible without opening the enclosure requires a driver to be installed. Not the Thunderbolt part, not the LTO drive, but the Void That Binds - the HBA.

To get your HBA working, especially on macOS you need to jump through a few hoops - something Canister's Preflight Checks helps with - but that's not what this post is about. It's about understanding that not every HBA is created equally, and why that matters.

Caught In A Trap

As LTO drives have quite a long lifespan, the tech surrounding it advances quickly: a new macOS version each year, the introduction of Apple silicon, Thunderbolt 3, and so on. Plus, every couple of years a new LTO generation is released that's bigger, faster, and better.

LTFS, the filesystem powering LTO, also evolves in tandem with new LTO hardware generations and macOS updates. It has seen a lot of improvements - not just for newer drives, but also for older ones. So much improvement that at some point you'll find yourself caught in a trap: an updated LTFS edition will only work with a specific macOS version, and worse, requires the HBA to be compatible with specific technology.

Back in the day, mLogic used to ship a certain Areca HBAs in mTapes with LTO-5 and LTO-6. With the advent of Apple Silicon and Big Sur, an LTFS version to support those LTO generations was released. However, packed with new technology and features, this particular HBA suddenly did not support the LTFS updates. It's not an issue you can get around — the drive simply won't write any data to tape.

There were only two options: go back to an old Mac, and stick to an older, inferior LTFS, or replace the HBA with a more recent model. While the former option seems appealing from a cost effectiveness approach, it isn’t the most feasible option in the evolving landscape of high-performance workflows.

Another example is when someone tries to build an LTO workflow on a shoestring budget. LTO drives are expensive, so it's tempting to pick up a used LTO drive from eBay. Especially SAS units - that are a bit more affordable, but also require buying a separate HBA. Often times, these end users fall into the trap of also buying a secondhand HBA, not realizing it might not work with their LTO drive at all. They finally assemble all moving parts, only to realize they had bought the incorrect components.

The solution

There are not a lot of companies that make SAS HBAs, but one stands out: ATTO.

ATTO's ExpressSAS HBAs are clearly designed for today’s data hungry applications, and perform great in non-room temperature environments. I'll make this quick: save yourself from a heap of headaches and get an ATTO HBA next time you need one.

That's it, that's the ~tweet~ blog. Have a nice day :)

Attending NAB? Come and checkout Canister for yourself at 📍SL10079 and book your demo now.