Just tested: if file metadata (last change time, access permissions ...) on NFS storage change, then all NFS clients invalidate the memory cache of the file completely. So, if your index does not get changed, caching is good on readonly slaves - the NFS client queries only file metadata sometimes. But if yout index changes, all affected files have to be read again from NFS. You can try this by "touching" the files.
fincore from linux ftools can be used to view the file caching status. "touching" a file on a local mount does not invalidate the memory cache. The kernel knows, that no file data have been changed. On 26.05.2017 19:53, Robert Haschart wrote: > The individual servers cannot do a merge on their own, since they mount > the NAS read-only. Nothing they can do will affect the index. I > believe this allows each machine to cache much of the index in memory, > with no fear that their cache will be made invalid by one of the others. > > -Bob Haschart > University of Virginia Library >
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