Less known Solaris Features: SamFS - Part 8: Usecases and future directions
Okay, after all this configuration. How can you use it? Well, the most obivous usage of SamFS is Archiving. And many customers use it for exactly this task: Archiving audio, archiving video, archving eMails, documents, xrays, satellite images, simulation data, data of large experimental system. Everything that´s worth to be stored for a long long time. That´s the job, it was designed for.
But there are more unconventional use cases. One example: What does a backup software for network use? The ones with a central server and a backup agent? For example for Oracle? Well, the client not really much more than triggering RMAN and transmitting it over the network. The server receives it and stores it into tape. The problem with it? Well, did you recently look into the price list for such an backup agent? Now think about the follwing idea: With SamFS you already have something, that controls your tape. everything written to a SamFS filesystem will be written to tape, if you configure it this way. Share this filesystem via NFS. Now you just have to write your RMAN script to backup your data into this NFS filesystem. No backup client involved. By the way, as the backup is written to the cache at first, you don´t have the problem of keeping the tape streaming at top speed (the start/stop problem is mostly something of the past, as most drives are capable of changing their speed in discrete steps to adapt the speed of incoming data. Of course you won´t use the full speed and the TB/hour capacity of the device). When you completed a backup file, SamFS will write it at full speed of the tape drive to the tape. The interesting point about SamFS: Once you think about it, about the concept of hierarchical Storage Management, about a filesystem with tapes in it´s background, you will find more and more interesting use cases for it.
Future directions and ideas
SamFS is a tool that is in active development at Sun, albeit we work on the integration of SamFS like features into ZFS. More interesting will be the hardware side of this system. I´ve used iSCSI based volumes in my example. Just think about this scenario if i didn´t used two 2G volumes but X4500 with 48 TB. Within 2 Racks i could archive almost 1 Petabyte with medium speed disks. (By the way: I´ve used the ZFS for the diskvols: Thus the transmission of the data to the network and the storage of the data itself is secured by checksums. ZFS Crypto will go beta soon, so you could can create an archive system where no data is unencrypted.) Using such large disk systems for archival is certainly a future direction. But there is still a need for tapes: Aircraft manufactures have to store their data for 99 years (as far as i know). A normal german company has to store their data for 10 years for our IRS equivalent called Finanzamt. You don´t want to store it on rotating rust for this amount of time. But by intelligent policies, you don´t have to hassle around with it manually.