If storage is to be virtualised and managed by policy, storage devices from many different vendors will need to talk to each other and to management software. "That's a big step from where we were-every time you bought a different brand, you had to learn a different management product," says Mark Heers, chairman of the storage networking industry association (SNIA) Australia and New Zealand. [Heers also works as marketing manager at storage vendor EMC, and is quoted later in this article as a representative of EMC.]
To ease the pain of managing storage, the SNIA has developed the storage management initiative specification (SMI-S), a standard aimed at allowing storage devices and management software to interoperate. "Standards are a by-product of things becoming common or popular to do. SAN standards have come out now because SANs are almost de rigueur for most medium and large customers now," says Heers.
Vendors are already beginning to release products compliant with the current SMI-S, but the capabilities are limited. "You can allocate storage to a specific server, report on that storage to find out how much is being used. I wouldn't describe it as having the depth that more sophisticated customers would look for," admits Heers. However, the SNIA will release new specifications every six to nine months, and these will offer increasing levels of sophistication.
| "At the moment, the policies are fairly simplistic... I think they'll get a lot more sophisticated and more in line with business requirement." Mark Heers, Chairman of the Storage Networking Industry Association (SNIA) Australia and New Zealand |
So in the end, does the existence of a standard actually prevent vendor lock-in? "For the majority of organisations who just want to do things in a normal way... the standard will suit them just fine," Heers says.
Those organisations looking to do something extra may need to look to the vendor-specific capabilities, however "it's going to be a trade-off because... going beyond the standard limits their choice or adds to their training costs. They know they're going beyond the normal standards and may be locking themselves into a reduced field of vendors, but that may give them a business benefit because it allows them to do something the standards don't encompass today," Heers explains.
Tiering
Not all storage is created equal. Different types of storage have different transfer rates and performance capabilities, different levels of availability, different backup and restore times, and of course different costs. And different kinds of data will require varying degrees of availability, performance, and restore time depending on how critical the data are to the business and how frequently they're used or accessed. It makes sense to store data from your critical applications on high-performance storage that's mirrored locally and offsite, but much less sense to go to that much trouble and expense storing someone's three-year-old e-mails that may never be seen again unless they get used as evidence in a court case.
"Customers are looking at tiering their storage, saying 'I need this level of retention for this sort of information, therefore we're going to use this level of performance and cost infrastructure'," says Bowden.
Part of a tiering strategy involves an intermediary layer of storage between your disk systems and tape backups called near-line storage. These devices consist typically of ATA disks-rather than the more expensive SCSI disks in high-performance storage units-and are most frequently used to store backups or snapshot images for several days before they are transferred to tape to be stored offsite. Since most restoration requests are made within 48 hours of data loss, storing backups on a near-line device for 72 hours or more could markedly reduce restore times over tape, according to a recent META Group paper. Furthermore, it would greatly reduce the amount of time staff spend hunting around for backup tapes in order to do restores. In the future, near-line storage may also be used as the primary location for less critical data that may still need to be accessed relatively frequently.
Tape still has an important part to play in a tiered architecture, because of its incredibly low cost. "As good as the cost improvements are in disk, we need other cost levels to keep stuff that we've got to keep for regulatory or compliance reasons but that we may not access very frequently," says Nieboer. "People have to start looking at storage holistically, and that includes recognising that there's a place for tape."
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