On Tue, Mar 21, 2017 at 6:06 PM, Mackay, Michael <[email protected]> wrote:
> Samikshan, > > Thanks for your suggestion. > > From what I understand, the read-only feature (which I had seen and > researched) is a client option for mounting the filesystem. Unfortunately, > we need the filesystem itself to be set up read-only, so that no one can > modify it - in other words, we need to make sure that no client can mount > it read/write. So, it has to be set up and started as r/o, and then the > clients have no choice but to get a r/o copy. > read-only xlator is loaded at gluster server (brick) stack. so once the volume is in place, you'd need to enable read-only option using volume set and then you should be able to mount the volume which would provide you the read-only access. > > Thanks > Mike > > -----Original Message----- > From: Samikshan Bairagya [mailto:[email protected]] > Sent: Monday, March 20, 2017 3:52 PM > To: Mackay, Michael > Cc: [email protected] > Subject: Re: [Gluster-devel] Read-only option for a replicated > (replication for fail-over) Gluster volume > > > > On 03/21/2017 12:38 AM, Mackay, Michael wrote: > > Gluster folks: > > > > Our group has a need for a distributed filesystem, like Gluster, that > can be mounted by clients as read-only. We wish to have the ability to > seamless switch over to an alternate source of this read-only data if the > default source fails. > > The reason for this ROFS is so that every client can get access to > applications and data that we want to ensure stays the same (unmodifiable) > for an entire system delivery life cycle. To date we've used read-only NFS > mounts reasonably well, but its failover performance is not at all great. > > > > We also don't want a "WORM" sort of arrangement - we want to prevent any > and all writes to the volume once it's up and shared. > > > > So, under the "how hard could it be" mantra, we took version 3.7.15 and > poked around a bit until we got it to do just what we want. It was a minor > mod to 'xlators/features/index/src/index.c' and > 'xlators/storage/posix/src/posix-helpers.c', along with a "force" option > when doing the volume start command. > > > > We would happily share the specific changes, and they seem to fit in the > 3.10.0 code base too; the question for the group is, would such a > capability be of interest to the Gluster baseline? Possibly a precursor > question (since I don't have much experience in gluster-devel at all, so > please forgive my approach if it's wrong) is, to whom should I pose this > question, if it's not to this group? > > > > Thanks for your time and I'd be happy to provide any further information. > > > > Hi Mike, > > Have you checked the 'features.read-only' volume option. Apparently you > can set it to on/off depending on whether you want your volume to be > read-only or not. By default it is set to 'off'. The following would make > your volume read-only for all clients accessing it: > > # gluster volume set <VOLNAME> features.read-only on > > Hope that helped. > > ~ Samikshan > _______________________________________________ > Gluster-devel mailing list > [email protected] > http://lists.gluster.org/mailman/listinfo/gluster-devel > -- ~ Atin (atinm)
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