We have a mix of SL3 (304, 305, 307) systems for desktops and compute servers, and a mix of NetApp filers and RAID-based PCs filers running various releases of SL and older RH. We have a problem where files created on NFS mounts from one node don't appear on other nodes for some time. Most of our mounts use TCP (this was done to get around other problems). All these mounts exhibit the above problem. we also have one older PC that uses UDP only, and so far nobody has seen the problems there. NetApp has suggested we set the "noac" option on the NFS mounts. We're concerned this will have a pretty noticeable performance hit. So we were wondering: 1) Is this commmon practice in clusetered environments? 2) Would something like actime=1 be better? 3) Would we have the same problem with SL4? Any and all feedback appreciated. Thanks, Miles