The headline grabbers in storage are usually the quick – flash, NVMe etc – or the harbingers of the next generation, such as the cloud. But in some ways these are the extremes, the outliers. In between, the vast bulk of the world’s business data resides on spinning disk hard drives and tape in long-term archives.
Of these, tape storage is set to see regular increases in capacity, with several other key advantages that make it likely to persist well into the future as the medium of choice for infrequently accessed data.
That was the key message in a recent article by Mark Lantz, manager of advanced tape technologies at IBM’s Zurich research facility.
In terms of its density, he said, we could soon see tape cartridges that run to hundreds of petabytes of data. That prospect came into view with the announcement last year by IBM of a new record in areal density for tape, based on nano-scale advances in tape and tape head technology.
That development could put 330TB on a standard tape cartridge, enough capacity for the contents of a bookshelf that would run from one end of Japan to the other, according to Lantz.
That’s not available yet, though, and maximum tape cartridge capacities currently run to about 15TB uncompressed (30TB compressed), while spinning disk HDDs can go to 60TB and flash drives to 30TB.
Nevertheless, for putting a lot of data in one place, Lantz is probably right to claim tape can claim top spot with the ability to build tape libraries that run to several hundred petabytes.
Tape also consumes no power when not in use, has failure rates several orders of magnitude lower than spinning disk, and the inherent offline “gap” between tape and the wider network provides a barrier to unauthorised access.
On top of all this, tape costs something like one sixth the cost of disk.
Of course, the kind of data you put on pricey flash is not the same as would go on magnetic tape; access times for tape are measured in seconds compared to milliseconds or fractions thereof for disk.
So, tape is best suited to infrequently-accessed data, and it seems to be the medium of choice for some of the biggest players in the cloud. Microsoft admitted in a roundabout way not too long ago that its biggest repositories of cold data are held on tape. Meanwhile, the last we knew, Amazon’s Glacier long term storage also relied on it.
And if tape fits the bill then you can be pretty sure it’s a future-proofed medium in the sense that tape capacities are set to scale – by about about 33% a year according to IBM – in a way that HDD and flash technology can no longer be due the limits on working in the media at ever smaller scale.
A lot of these are quite convincing arguments, but, there’s one key trend of contemporary IT that tape cannot fit with.
That’s the drive towards analytics, or at least not the kind of online analytics that seems to be on trend right now.
Many storage and backup vendors are increasingly working analytics into their offer, and this mirrors the trend of digital transformation in which organisations are going fully digital, with the aim, at least in part, to gain value from existing data.
That’s entirely possible as long as data resides on constantly-available media. But tape, with its long access times, precludes this.
Sure, you can access batches of data at a time from tape repositories and then run the numbers, but this isn’t analytics as it forms part of current trends.
So, tape is ideal to store very large amounts of data that you don’t need to access very often, but its use cases seem to be gradually narrowing as the need to apply intelligence to archives increases.
Tape doesn’t seem likely to die for some time yet, but it may be the case that, as advances are made elsewhere in IT, its field of operations will shrink.