From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Barton Date: Tue, 23 Nov 2010 17:20:58 -0000 Subject: [Lustre-devel] Stripe offset default Message-ID: <016b01cb8b32$cc3a9c90$64afd5b0$@com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org Nick Cardo at NERSC mentioned at the LUG, and again when I chatted with him at SC10, that setting the default stripe offset is positively dangerous. I think he has a point. Setting file layout precisely can be essential for applications that know precisely what they're doing and want to control how aggregate OST load is balanced. But the default file layout is another matter entirely. Setting the default to a fixed layout, or even just a fixed starting OST has got to be the most direct path to achieving OST load imbalance. 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. Thoughts? P.S. Do people also agree that setting user/group/ACL permissions on OST pools would be a Good Thing? Cheers, Eric Eric Barton CTO Whamcloud, Inc.