Re: mmap support with a dfuse-mounted posix conntainer


Faccini, Bruno
 

Ok, I can reproduce the behaviour you have reported.

 

Having a look to the related source code, this may come from the fact if caching is disabled, DFuse automatically/silently switches to direct-io mode, but then we may trigger the current Fuse Kernel module limitation that cause shared mmap() mappings to be  unsupported (ENODEV).

 

 

From: <daos@daos.groups.io> on behalf of "shmatsuu@..." <shmatsuu@...>
Reply to: "daos@daos.groups.io" <daos@daos.groups.io>
Date: Tuesday 31 May 2022 at 13:57
To: "daos@daos.groups.io" <daos@daos.groups.io>
Subject: Re: [daos] mmap support with a dfuse-mounted posix conntainer

 

Hi Bruno,

Thank you very much for checking! I'm using DAOS v2.0.1.One thing I forgot to mention previously is that I mounted the POSIX container with dfuse "--disable-caching" and got an error from mmap. Yes, without "--disable-caching" option, mmap succeeds with no errors in my environment as well. If you try to do dfuse mount with --disable-caching option, in your environment, does mmap succeed? I wanted to know if this is an expected behavior and to evaluate the effectiveness of caching in dfuse.

Thank you very much for your help,
---
Shohei

---------------------------------------------------------------------
Intel Corporation SAS (French simplified joint stock company)
Registered headquarters: "Les Montalets"- 2, rue de Paris,
92196 Meudon Cedex, France
Registration Number:  302 456 199 R.C.S. NANTERRE
Capital: 5 208 026.16 Euros

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.

Join daos@daos.groups.io to automatically receive all group messages.