[lyind]

This nice approach has at least these drawbacks:

1. Swapping drives is hard

   * may be overcome by declaring failure domain = node

2. No powerloss protection advertised to OS, ie. slow synchronous writes

   * may be overcome by software hacks and whole-system battery supply

3. Potential slowdown on continuous write load (weeks or months, depending on drive)

   * may be overcome by software in _some_ situations

At least the last two points are a no-go for enterprise use-cases, if not addressed.

[eqvinox]

I'm gonna claim that this card isn't aimed at enterprise use-cases that need this kind of service. I'd put it along the lines of "nearline SAS" HDDs, aimed at non-critical applications where you care more about bulk capacity than reliability.

Relatedly, M.2 SSDs are inherently slower than the same pile of silicon in an U.2/2.5" form factor — the power/heat budget is noticeably lower.

[ciupicri]

> No powerloss protection advertised to OS

How can the OS (I'm interested in Linux) know about this feature?

[wtallis]

Enterprise SSDs almost always include power loss protection capacitors on the drive itself, so the drive can either directly advertise that it's write caches are non-volatile or simply ignore cache flush requests from the host since data in the cache can already be considered durable from the host's perspective.

Unfortunately for this product, enterprise M.2 SSDs are almost always 110mm long rather than 80mm long, precisely because of the space taken up by those capacitors.