From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher J. Morrone Date: Tue, 23 Nov 2010 14:59:23 -0800 Subject: [Lustre-devel] Stripe offset default In-Reply-To: References: <016b01cb8b32$cc3a9c90$64afd5b0$@com> <4CEC1AB8.2040507@llnl.gov> Message-ID: <4CEC474B.1010609@llnl.gov> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org On 11/23/2010 01:19 PM, Andreas Dilger wrote: > On 2010-11-23, at 12:49, Christopher J. Morrone wrote: >> On 11/23/2010 09:20 AM, Eric Barton wrote: >>> I believe, now that lfs setstripe uses options rather than positional >>> parameters, that the risk of unintentional errors is much less. But >>> that still leaves the filesystem vulnerable to na?ve or malicious >>> users. So I propose that we should continue to check permissions >>> normally when setting the default stripe _count_, but restrict the >>> ability to set a specific default stripe _offset_ to the superuser. >> >> At the very least bug 18547 MUST be completed before doing this. >> Lustre's default layout mechanism is too uneven, and leads to too much >> of a performance problem right now to take away users' only ability to >> lay files out evenly on their own. > > I guess the subtle distinction in Eric's question is for "default striping parameters specified on a directory" and not "striping parameters set on a per-file basis". In IRC I discussed with Eric that it is like that specifying the starting OST on a directory default layout is _probably_ not what a user wants to do. Ah, ok, I did miss that. I am less opposed to that, since I can't think of a particularly compelling use case for a fixed offset default on directories.