It looks like 'sync' is the problem grep NAS1 /etc/auto.nfs4 NAS1 -fstype=nfs4,_netdev,rw,proto=tcp,sync,... xen01.loc:/ rm -f /mnt/NFS4/NAS1/file.out && \ time dd if=/dev/zero of=/mnt/NFS4/NAS1/file.out bs=32K count=3K 3072+0 records in 3072+0 records out 100663296 bytes (101 MB) copied, 485.721 s, 207 kB/s real 8m5.861s user 0m0.012s sys 0m0.250s Change mount 'sync' -> 'sync' vi /etc/auto.nfs4 - NAS1 -fstype=nfs4,_netdev,rw,proto=tcp,sync,... xen01.loc:/ + NAS1 -fstype=nfs4,_netdev,rw,proto=tcp,async,... xen01.loc:/ systemctl restart autofs Repeat rm -f /mnt/NFS4/NAS1/file.out && \ time dd if=/dev/zero of=/mnt/NFS4/NAS1/file.out bs=32K count=3K 3072+0 records in 3072+0 records out 100663296 bytes (101 MB) copied, 1.65577 s, 60.8 MB/s real 0m1.658s user 0m0.000s sys 0m0.089s I'd expect 'sync' to be slower than 'async', but 300X ? The NFS default is 'sync' for a reason -- integrity of the data. At this performance hit, it's not a realistic option. What can be optimized to get 'sync' back in the game? Or is there possibly another dependency - kernel? netwk stack? other? - that's involved? LT -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org