On Thu, Feb 13, 2014 at 11:29 AM, Gionatan Danti <g.danti@xxxxxxxxxx> wrote: > On 02/13/2014 12:37 PM, Jeff Layton wrote: >> >> >> Using cache=none sort of defeats the purpose. After all Gionatan said >> that he was doing this specifically to use fscache, and that won't work >> with cache=none. >> > > Surely my idea was to use FSCACHE to speed up remote access. Without it, the > entire discussion is pointless... > > >> But, lets leave that aside for a moment and consider whether this could >> work at all. Assume we have samba set up re-share a cifs mount: >> >> Client sends an open to samba and requests an oplock. Samba then opens >> a file on the cifs mount, and does not request an oplock (because of >> cache=none). We then attempt to set a lease, which will fail because we >> don't have an oplock. Now you're no better off (and probably worse off) >> since you have zero caching going on and are having to bounce each >> request through an extra hop. >> >> So, suppose you disable "kernel oplocks" in samba in order to get samba >> to hand out L2 oplocks in this situation. Another client then comes >> along on the main (primary) server and changes a file. Samba is then >> not aware of that change and hilarity (aka data corruption) ensues. >> > > Are you of the same advice for low-frequency file changes (eg: office > files)? > > What about using NFS to export the Fileserver directory, mount it (via > mount.nfs) on the remote Linux box and then sharing via Samba? It is a > horrible frankenstein? > > >> I just don't see how re-sharing a cifs mount is a good idea, unless you >> are absolutely certain that the data you're resharing won't ever >> change. If that's the case, then you're almost certainly better off >> keeping a local copy on the samba server and sharing that out. >> > > After many tests, I tend to agree. Using a Fedora 20 test machine with > fscache+cachefilesd as the remote Linux box, I had one kernel panic and > multiple failed file copies (with Windows complaing about a "bad > signature"). > > I also found this: https://bugzilla.redhat.com/show_bug.cgi?id=646224 > Maybe the CIFS FSCACHE is not really production-grade on latest distros > also? I have not found fscache to be a problem in my tests, but did find problems with Samba 4.1 reexporting cifs directories. I am investigating this so any log information that you have or additional problem determination details would be appreciated. -- Thanks, Steve -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
