Devices to test DAX Support

[Phani Arava]

Iam looking at devices that support DAX filesystem (large size in 100s of GBs, so i cannot emulate memory). 

Will Intel 3d xpoint SSD 900p work ?

Regards

Phani

[Andy Rudoff]

Hi,

The whole point of DAX is to give you direct load/store access, like memory, so you need devices that are accessed like memory.  Of course, all the usual file APIs work on DAX (open, close, read, write, mmap, msync) and all those also work on non-DAX file systems.  The non-DAX file systems will just use paging, transferring blocks into the system page cache as necessary.  So nothing is preventing you from developing code on non-DAX file systems since all the APIs work and memory mapping a file from a fast SSD like the Optane SSD will not use DAX, but it will page blocks in and out of storage very fast.  The only difference would be performance, so if your goal is to gather performance information on DAX, I suggest you use persistent memory or emulate it volatile memory.

-andy