Storage Standards Could Jump-Start Interoperability

The Storage Networking Industry Association is working to create RAID interoperability and a multipath specification.

Standards and storage vendors have mixed about as well as oil and water for most of the past decade. However, with vendors intent on climbing the technology stack into information management and with IT managers demanding flexible storage options, now is a good time for standards to take hold.

The Storage Networking Industry Association, which includes many major vendors in the storage arena, is working to create RAID interoperability and a multipath specification. It is continuing to develop its crucial SMI-S (Storage Management Initiative Specification). SNIA officials discussed these initiatives in a recent briefing with eWEEK Labs.

SMI-S, which aims to standardize storage management tools, is SNIAs most important standardization effort; the association is working to add support for iSCSI, NAS (network-attached storage) and tape library devices.

/zimages/4/28571.gifClick here to read about how iSCSI and NAS are revving IP-based storage.

SNIA also seeks to expand SMI-S to include management of virtualization technology, security and performance in the future.

Although raid is a well-known, mature technology, every storage vendor implements it differently. This disparity dims any hope of interoperability among RAID solutions. SNIA, therefore, is advocating a Common RAID DDF (Data Disk Format) that will allow IT managers to move disks from one storage system to another.

DDF-compliant products are expected to ship next year.

In addition to letting IT managers move from one storage system manufacturer to another, DDF will easily allow upward migration. For example, IT managers will be able to move from inexpensive software-based RAID to high-end storage controller RAID solutions as the need for performance and reliability grows.

In the realm of server management, DDF will be extremely useful because it will allow IT managers to migrate smoothly from internal storage from older servers (or dead ones) to new servers. Today, if a server with ROMB (RAID on Motherboard) fails, an IT manager must buy a new server with nearly identical specifications to the fallen server to quickly recover the data on the old disks.

With DDF, an IT manager will be able to easily move data disks to a new server, simplifying data migration.

SNIAs multipath management API working group is trying to hammer out interoperability issues in SANs (storage area networks).

Multipath uses multiple switches and HBAs (host bus adapters) to design resilient SANs. The technology is essential for failover and for load balancing storage traffic on SANs, so interoperability will be key for this technology.

The API draft, which is in its initial stages, will allow management applications to discover multipath devices (regardless of vendor) on a SAN and identify network paths that storage traffic will use. A weighting system, which would allow IT managers to prioritize traffic running through the SAN, has also been proposed.

Senior Analyst Henry Baltazar can be reached at

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