making storage intelligent and stealing functionality from the server
One of the hottest concepts in the SAN marketplace today is the advent of server-free backup. In the projected scenario, on your basic SAN (as visualized by countless marketing slides), there will be intelligence residing in the SAN to perform the data movement function of a backup. Here's how it plays out:
- there is a master server that maintains a catalog of all data on the SAN. This has been called meta-data, or data about data.
- That server will periodically perform a backup of said data by instructing a device on the SAN to move the data from Point A to Point B. Point A is typically disk, and Point B is typically tape.
- The data mover device will perform the actual movement at a block level from disk to tape or disk to disk. There is no IO occurring on the server to make this happen.
- Once the data has been copied from disk to tape, the data mover device will inform the server of completion.
- The master server will update it's catalog with the information about the backup tape volume, library location, etc., and proceed with the next backup.
The general idea behind this is that it will cut out the requirement for a dedicated server to perform backups, it will speed up backups so that they finish in a far more timely manner, that CPU cycles will not be consumed by overhead tasks like backup, and customers will have greater control over the entire backup process.
You can easily see the potential for other applications of server-free data movement, like snapshot copies and the like.
Currently, the storage router mfrs., like Crossroads, and hub/switch vendors like Gadzoox and Brocade, have announced support for server-free backup. Crossroads and others have demoed data movement at various industry shows, per their press releases. The hold-up today is that the software mfrs., like Legato and Veritas, have to provide the enabling software for the server. All of the major backup software vendors have announced support for the data mover functionality. We should see products soon, but I can't put a time frame on "soon."
buck |
