[Beowulf] Tiered RAM

Chris Samuel chris at csamuel.org
Wed Sep 26 03:20:12 PDT 2018

On Wednesday, 26 September 2018 1:38:15 PM AEST John Hearns via Beowulf wrote:

> I had a look at the Intel pages on Optane memory. It is definitely
> being positioned as a fast file cache, ie for block oriented devices.

Interestingly there was a (non-block device) filesystem presented this year
called NOVA targeting these sorts of NVMM devices.  LWN has a nice little
article on it (which in turn links to earlier articles on it, and the original


It's still going through rapid development and (learning from the btrfs
experience) the kernel folks aren't going to let it in without a working fsck
from the sound of things.

There's also some NVDIMM documentation in the kernel tree which is pretty
heavy going, I've just tried to skim it and I think I know less now than when
I started. ;-)


There's also the more readable documentation for the "block translation
table" which seems to be intended to provide a way to give some atomicity
to storage transactions to NVDIMMs which are not present given the nature
of the hardware:


There is also the persistent memory wiki:


> This worked by tiering RAM memory - ie a driver in the Linux
> kernel would move little used pages to the slower but higher capacity
> device.
> I though the same thing would apply to Optane, but it seems not.

Well the simplest way to get what you describe there might be to use
the Optane as a swap partition. :-)

Red Hat have some docs about using NVDIMMs.


Not sure I helped much there! :-)

All the best,
 Chris Samuel  :  http://www.csamuel.org/  :  Melbourne, VIC

More information about the Beowulf mailing list