I don't go much for spanning or multi-drive striping for most personal or business uses.
About the only time RAID-5 makes sense (to me at least) is when you have something like an accounting or web application that can't experience unscheduled downtime for any reason. Usually because it interrupts "the flow of commerce" (i.e. sales) or some other key business function like issuing support tickets or software licenses to your customers. Having RAID allows you to stay up long enough to announce a maintenance period and get a good backup before you rebuild your array.
And don't be fooled by the "live rebuild" argument that says you can hot-swap and rebuild without taking your array offline. Yes, it can
be done. But it's slow, and frustrating, and it drags server performance down so much that it's not practical for general purposes. About the only time it is viable is if you implement load balancing with automatic 'fail-over' to a secondary server that takes on the burden until the primary array gets rebuilt. Once again we're talking heavy-duty data center setups here. If you're something like a bank - go for it. Otherwise put it out of your head. <EDIT/UPDATE: see StoicJoker's comment below before taking the above as gospel. >
Spanning is something I really don't understand except for very specialized circumstances - like streaming data collection, or media rendering. Basically where you don't know how big a file will be, other than it's gonna be humongous! Nothing can ruin your morning more then to discover your CGI project (which had been rendering for over 28 hours) aborted at the "94% completed" mark because it was a few hundred megabytes shy of the drive space it needed to finish. I've seen it happen. (There were tears...)
Pooling may be useful for a home media server. Especially where the owner is generally clueless about technology and keeps loading DVD after DVD rip onto their box. For people like this, pooling is probably the easiest and most practical approach. Run out of space? Just slap in another drive and add it to the pool.
But as Stoic pointed out above, it's still a dicey chance to take if it's data that's hard to replace or genuinely important to its owner.
Over time, I've begun to see the space limitations on physical drives as a blessing in disguise. The bigger the drive, the more disorganized they seem to become. And thanks to disk index/search utilities like Everything
, most people can get away with it. Fling your stuff in folders - and put folders within folders out the kazoo - and screw organization! Just use a utility to root out where you put something when you need it.
It works. But it's sloppy. And it's not a generally good way to handle file organization.
FWIW, I tend to assign specific
types of data. That allows me to more easily setup backup and sync routines on a case by case basis. Critical files and directories may get mirrored in real time. Other directories may require version control. Others may get simple backups. Some don't get copied or backed up at all since they're kept for convenience and easily replaced with newer versions should they ever be lost. (Linux distro ISOs or Microsoft's WSUS files are a good example of that.)
Simpler is better when it comes to drive and directory setups. Especially
on servers. And extra especially when you're as simpleminded as I am about these things.