Why pick a NAS over a "normal" NFS share? [duplicate]
From an end-user perspective, what is the difference between a NAS device and using NFS exports from a file server?
They seem to accomplish the same end result.
The difference between a SAN and other file storage is related (in my experience) to how they are connected to the server infrastructure.
However, the difference between a NAS, connecting over a standard ethernet port, and NFS (sharing storage off specific servers, also over the network), seems more nebulous.
Is there a good reason to pick a NAS filer over just running NFS on servers?
Solution 1:
A NAS (Networked Attached Storage) is a device serving files via the network. One protocol to accomplish this is NFS. So a NAS can use the NFS protocol (or another protocol).
So a Linux server providing NFS exports is, in effect, a NAS device.
Is there a good reason to pick a NAS filer over just running NFS on servers?
The appliance has the advantage of being pre-packaged and ready out of the box and probably has a web gui to make changes a little more admin friendly. A disadvantage to the appliance is that recovery of the data could be more difficult, if you get in that spot, as the underlying filesystem could be proprietary.
Solution 2:
This is an oddly-worded question - it's like saying "What's the difference between fruit and an apple" - one is a class, one is a member of that class.
NAS contribute to a general-purpose network by only sharing one or more protocols that can include NFS.
NFS is a protocol that can be shared from one or more devices on a general purpose network, these devices can share only using NFS or simultaneously with other protocols.
True SANs contribute to storage-specific networks.
iSCSI blurs the issue as it can share over a general-purpose network (i.e. NAS-like bahaviour) but at the block level (usually a trait of SANs).
To answer your final question more directly, pick a NAS where you want a single, often more highly-available (i.e. dual-controllers, PSUs, storage-path, NIC), centralised, and importantly centrally-managed, solution and use a multi-point NFS solution where budgets are perhaps tighter, data availability is perhaps lower and skills to manage across multiple machines is available.