Traditionally hard drives have stored information -- and storage interconnects have transmitted it -- in same-sized blocks of data. Another likely trend is a move away from "block storage, which has been dominated by the SCSI interface, to something that is a higher level of abstraction, what we would call object-based access," says Kandlur. An object is a variable-length piece of data stored in a block device such as a database record or an e-mail message, he explains. "The storage system would have better ability to provide higher-level operations on these objects."
The problem with block-based storage is that objects consist of a large number of blocks, and without any level of abstraction, keeping track of where all those blocks are can take up significant resources on the host system trying to access that data. "This can be a limitation to scalability and providing a finer grain of access control to these objects," says Kandlur. "If you go to an object-based model, the storage system can provide you with a finer level of security and access control -- it can be at the level of an object or collection of objects." This object-based model is a precursor to the virtualisation and information lifecycle management concepts we discussed previously.
Keeping the disks spinning
In the previous feature, we discussed how storage management will eventually evolve from a separate discipline, as it is today, into just another part of the enterprise's IT management system. "Why have storage as a separate discipline, why not just have it managed in the same way you manage your network infrastructure and your server infrastructure?" says Selway. McIsaac believes part of this evolution will be the management of storage plumbing -- fibre channel, iSCSI, etc -- becoming part of the networking manager's role, rather than the storage manager's. "By about 2008 or 2009, the networking guys will probably manage the storage networks as well," he says. "It may even be that you still have separate networks but they may be all in one device. Switches will handle both IP traffic and fibre channel at the same time, but they'd be one big set of switches."
The switches themselves are likely to have increasing levels of intelligence built in. "The major switch players -- Brocade, Cisco, McData -- have either developed or acquired intelligent switches," says McIsaac. "Rather than being the old-fashioned low-level, low-layer switches that just pass packets through and route them, these new ones are more like the intelligent routers that you have in IP. They can break open the Fibre Channel or iSCSI packets and do some interesting inspection of the data, and then might do routing in the switch based on the data itself." Currently even the lowest level operations such as replication and backup must go through a convoluted path from one storage device, through the switch to the server running the storage management software, then back through the switch to another storage device. The advantage of putting more intelligence into the switch is "some of the things that are done in the disk array or in the virtualisation software can eventually moved into the network. Some of the simpler stuff like replication actually gets moved into the switch without having to bother the host," explains McIsaac.
More of the same
The future of storage hardware at first glance seems to be going in all sorts of directions, but the underlying trend is the usual one of bigger, better, faster, cheaper. Although there are fundamental difficulties to overcome, improvements to existing technologies are likely to fill the gaps for the foreseeable future. Eventually, either holographic or atomic storage, or some new technology will take over. For the time being, though, disk, tape, and optical are where it's at.
This article was first published in Technology & Business magazine.
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