Recent weeks have seen a fascinating discussion emerging in the storage area of the LinkedIn business networking site on the merits of disk versus tape. Its the old story: tape is old but reliable and uses zero energy while it's storing archived data. Coming up on the rails, assisted by a number of energy-saving and technologies, is disk technology which is being increasingly used for even archived storage because it's faster and familiar.
Storage pros -- as well as a few vendors with the obvious axes to grind -- have been hashing out the arguments for and against the two technologies. What's clear is that disk now has significant mindshare, especially when combined with deduplication, even -- for some -- for archiving. However, for most, tape stays on top for deep, long-term archiving. It remains an attractive option, not just because of its energy-efficiency, but also because of the considerable amount of expertise and equipment in which large corporations have invested over the decades.
Another argument is that tape is cheaper. As one contributor put it: "Depending on the size of the environment and the change rate, the cost of spinning disk can quickly exceed that of physical tape. The optimal solution is to utilize a non-tape methodology for backup that also has the ability to 'copy to tape' for long term archive. If this can be done after replication to a remote DR site, all the better."
Some take a more nuanced view, seeing disk as simpler: "When you use deduplicated disk as a target, and when the disk does not emulate tape - that is, disk as disk - you significantly reduce the complexity and incidents of backups. You no longer have to capacity-manage, schedule and deal with incidents surrounding libraries (physical or real), tape drives (physical or real) and tape cartridges (physical or real)."
The key issue is how you define backups and archives - although one contributor’s take on this was: "Tape is for backups you never plan to use. It's not something you want to bet the life of the enterprise on." Though that sounds contrary, it was a position none could disagree with: "Tape is good for long-term backup. Backups from 60 days or older, which must be kept for compliance, and which will (hopefully) never be needed. Tape is good as a recording if you will of the life of your information. Very few operational restores occur after 30 days. And if so, they are individual items and not full server restores."
It was summed up by one storage consultant: "Each technology has its place. In our datacenters there is more data on tape than ever before. The costs of both technologies is decreasing. Both will stay since there is no good alternative. They are keeping each others alive. If you need to restore fast ,you don't want to wait from retrieval from tape, so you do that from your dedup device, VTL or plain disk. If you have to store large amounts of data over a long period of time you use tape."
Is tape dead? No way.