Every now and then, but not as frequently as you’d imagine, I get asked about LTFS support so I was interested to read Chris Evans comments from IP Expo and have one or two quick comments of my own in response.
The questions I get tend to be in the context that ‘my vendor says this is the greatest tasting soup ever’ and a quick drill down leads me to suspect people never get around to the implementation today part of the conversation, but that’s a different post.
To declare the personal bias upfront I absolutely wake up in the morning and believe that the LTFS tape as disk concept is ridiculous and borne out of desperation. I won’t elaborate on that as that too is a different post but having declared that personal bias I’m going to walk away from it for now and take a more analytical view.
Looking at the reflection in a Zilla’s eye when we size up vendor support for LTFS what strikes me is we have now three drive manufacturers writing their own driver software for each platform they want to offer the functionality on. So the interface software burden moves from the backup software provider to the backup hardware provider. Maybe if you're a backup software provider you think that's a good thing, or not, it's a personal opinion as to if that's where the coding should be done, what the update schedule should be and how long you’re willing to wait for support to be current?
Moving from where the interface work should be done and looking at formats, why do backup software vendors have proprietary formats? Quite simply because to their information management system (Backup software) they need to represent hundreds of thousands, millions, tens of millions, billions, tens of billions (and so on) of files in some form of file system (I'm being very loose with that term) which is distributed across various different pieces of media, some of which could be offline, where the native file systems of each could not support anywhere close to that file density used directly.
Right now with each LTFS cartridge being it’s own piece of DAS, like it were an external hard drive or optical disc, managing those won’t be too bad when you have a handful of them. When it’s a box or a crate of them you’re going to want another layer of software over the top. And before you know it, we’re back to backup applications and their need to represent everything as a consistent file system all the time regardless of the active/offline state of physical components of that file system.
There are very solid technical reasons as to why backup applications developed in the fashion that they have and many of those technical reasons remain unchanged to this day.
The incredibly glib but correct answer to solving the challenges involved in differing formats and data mobility is to actually backup less data and retain it for much shorter amounts of time.
When we hold onto information for more than a year we might as well be holding onto it forever.