Re: No VMware?
Upvoted for the great response.
I agree with many of the points here, but I do wish to caution Hugo@Datrium on a couple of sleight of hand maneuvers. I would suggest going back and reading the first two paragraphs of the article:
'A Storage Area Network (SAN) is, according to Wikipedia, "a network which provides access to consolidated, block level data storage... A SAN does not provide file abstraction, only block-level operations. However, file systems built on top of SANs do provide file-level access, and are known as shared-disk file systems."
'Techopedia says: "A storage area network (SAN) is a secure high-speed data transfer network that provides access to consolidated block-level storage. An SAN makes a network of storage devices accessible to multiple servers."'
Discussing an Array capability in terms of the benefits that a SAN offers is misleading. Conversely, *criticizing* an array because it lacks those SAN features is disingenuous. What's worse, the fact that there are implementation differences within and without the protocol standards means that vendors can (and do) use the protocol as they require to achieve the results they desire.
For instance, let us take your point (2) above. "If one does not use NVMf [sic] to connect to a traditional array, it's controller standsa between the host and the NVMe storage device." It seems to me that if you are *not* using NVMe-oF to connect to an array, the question of whether or not NVMe-oF "is a SAN" is moot. There is no definition of SAN (of which I am aware) that requires an array storage controller.
[Which brings up another point: Part of the problem here is that the word "controller" is used so many times that it becomes difficult to keep these items separated. There is a controller for the FTL, there is a controller for the NVMe subsystem, there can be a controller for the storage array, etc. In SDS implementations, there is a controller for the control plane too. Controllers, controllers everywhere! :)]
Resiliency in NVMe-oF systems is indeed a major question, and I completely agree with most of the caveats Hugo mentions in (3). Once again, though, we have a "shifting goalposts" argument. "I'm not aware of such a
- distributed volume manager
- with erasure coding efficiencies
- in widespread use today."
I break this down specifically like this to illustrate that at any point Hugo can point to that last prepositional phrase, "in widespread use today," as the clincher. Then again, with the nascent timeline of development for NVMe-oF drivers to begin with, claiming *any* NVMe-oF deployment as "widespread use" would be at best, wild-eyed optimism.
Nevertheless, the question at hand is one of the technology, not one of the deployment status. I would argue that at the core, the implementation of NVMe-oF as a SAN is indeed possible (technically speaking), and that such features and benefits of SAN deployments can be transferred over to NVMe-oF - even if it happens to be an eventual achievement.
One note on NVMf vs. NVMe-oF. I agree that NVMf is shorter and while I prefer the shortened method myself, I've come to learn that many companies using the non-standard nomenclature also have non-standardized NVMe-oF implementations. It's becoming a very quick litmus test to determine whether or not the implementation is the standard version or not. So much so, that I automatically make the (often correct presumption) that companies using NVMf in their literature are *not* using standards-based NVMe-oF. Again, it's my perception having worked with and talked to many NVMe-based companies.