SAN or NAS 100-200TB - where to start looking? [closed]

I concur with the NexentaStor suggestion, but since I work for Nexenta I suppose that's expected. Bear in mind no matter whom you go with, big storage (which 200 TB would qualify as, if on the low end) really requires some grasp of your use-case(s) and a discussion with a qualified storage engineer if you don't want to end up with something that is at best over-powered for your needs, and at worst far under-powered for your needs. There's a discussion to be had about what you intend to do with it (all uses), and where in the triangle you sit.

The triangle is the big 3 parts of storage, and the old saying goes (well, there's many variations of it, but here's one):

Capacity, Performance, Redundancy -- pick two.

No matter who you go with (and I always recommend shopping around), talk through your use-case with someone there, and make sure you get a SAN that's suited for your needs (and when in doubt, always err on the side of caution; a slightly over-built SAN is a good problem to have, as opposed to an under-built SAN and the terrors it can bring you).

I'd also suggest that unless you have a compelling reason for it, 1 system holding 200 TB may be a bad place to start. Perhaps go with 4 systems each holding 50 TB, or 2 systems holding 100 TB each, as safer (failure doesn't lead to 100% outage) and higher performance alternatives.

The decision between SAN and NAS is whether you want the file serving to be done on the storage or the servers you attach to it. If you choose SAN, you will have users accessing files through normal file servers (whatever flavor you use), which access what they see as a hard drive through some sort of SCSI based block protocol. If you go with a NAS, you will get files served directly from the same device that manages the hard drives.

NAS products tend to generally be less sophisticated when it comes to hard drive management. Also, they tend to be not as good at serving files as a file server would be. They're either more expensive or less scalable. Since disk scaling and file services scaling are accomplished by upgrading the same box, you risk running out of headroom on one but not the other.

SAN products tend to focus on the disk. They'll have better performance and redundancy/reliability on the disk side, but file functionality (if it exists) will be less good than a NAS or a file server.

There are a couple of integrated boxes that started off life as a NAS or a SAN and now do both, with varying levels of success.

PogoStorage, using NexentaStor and ZFS - http://www.pogostorage.com/products/nexenta/overview/comparison.php