I've posted here about this a number of times. The other admin I work with had been playing with it recently, with some real problems we'd been having, and this time, with a year or so's more stuff to google, and newer documentation, found the problem. What we'd been seeing: cd to an NFS-mounted directory, and from an NFS-mounted directory, tar -xzvf a 25M or so tar.gz, which unpacks to about 105M. Under CentOS 5, on a local drive, seconds; doing the above, about 35 seconds. Mount options included sync. Under 6.x, from the beginning, it was 6.5 to 7 *minutes*. The result was that we'd been keeping our home directory servers on 5. What he found was the mount option barrier. According to one or two hits I found, googling, it's not clear that 5.x even recognizes this option. From upstream docs, <https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/writebarrieronoff.html>, it's enabled by default, and affects *all* journalled filesystems. Remounting the drive with -o nobarrier, I just NFS mounted an exported directory... and it took 20 seconds. Since most of our systems are all on UPSes, we're not worried about sudden power loss... and my manager did a jig, and we're starting to talk about migrating the rest of our home directory servers.... mark