When FS Attribute caching is allowed:
It is allowed for read-only services. It should work for all doors. 
Attribute caching can lead to PNFS updates made on one node not visible in another node that mounts the same PNFS. nodes running encps and pnfs manager should not enable caching. We use Pnfs as a data pipe in some cases. NFS 2 does not allow server driven invalidation of cache. It is available in NFS 4, but we do not use it. SRM checks file sizes though locally mounted Pnfs, so caching should be off too.