From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [C/R v20][PATCH 38/96] c/r: dump open file descriptors Date: Sun, 21 Mar 2010 17:27:03 +0000 Message-ID: <20100321172703.GC4174@shareable.org> References: <1268960401-16680-1-git-send-email-orenl@cs.columbia.edu> <1268960401-16680-4-git-send-email-orenl@cs.columbia.edu> <20100320044310.GC2887@count0.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andreas Dilger , Oren Laadan , linux-fsdevel@vger.kernel.org, containers@lists.linux-foundation.org To: Matt Helsley Return-path: Received: from mail2.shareable.org ([80.68.89.115]:39901 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752539Ab0CUR1N (ORCPT ); Sun, 21 Mar 2010 13:27:13 -0400 Content-Disposition: inline In-Reply-To: <20100320044310.GC2887@count0.beaverton.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Matt Helsley wrote: > > That said, if the intent is to allow the restore to be done on > > another node with a "similar" filesystem (e.g. created by rsync/node > > image), instead of having a coherent distributed filesystem on all > > of the nodes then the filename makes sense. > > Yes, this is the intent. I would worry about programs which are using files which have been deleted, renamed, or (very common) renamed-over by another process after being opened, as there's a good chance they will successfully open the wrong file after c/r, and corrupt state from then on. This can be avoided by ensuring every checkpointed application is specially "c/r aware", but that makes the feature a lot less attractive, as well as uncomfortably unsafe to use on arbitrary processes. Ideally, c/r would fail on some types of process (e.g. using sockets), but at least fail in a safe way that does not lead to quiet data corruption. -- Jamie