Messages in this thread | | | Subject | Re: Cleancache and shared filesystems | From | Steven Whitehouse <> | Date | Tue, 31 May 2011 09:58:26 +0100 |
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Hi,
On Fri, 2011-05-27 at 16:33 -0700, Joel Becker wrote: > On Fri, May 27, 2011 at 05:19:39PM +0100, Steven Whitehouse wrote: > > + if (ls->ls_ops == &gfs2_dlm_ops) { > > + if (gfs2_uuid_valid(sb->s_uuid)) > > + cleancache_init_shared_fs(sb->s_uuid, sb); > > + } else { > > + cleancache_init_fs(sb); > > + } > > Hey Dan, > Steven makes a good point here. ocfs2 could also take advantage > of local filesystem behavior when running in local mode. > > Joel >
There is a further issue as well - cleancache will only work when all nodes can see the same shared cache, so we will need a mount option to disable cleancache in the case we have (for example) a cluster of virtual machines split over multiple physical hosts.
In fact, I think from the principle of least surprise this had better default to off and be enabled explicitly. Otherwise I can see that people will shoot themselves in the foot which will be very easy since there is no automatic way that I can see to verify that all nodes are looking at the same cache,
Steve.
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