Narrowing doen the issue, NFSv4 file xfer with 'sync' appears, here, to be ~ 300X slower than with 'async'. (1) for NFSv4 mount with 'sync' grep NAS1 /etc/auto.nfs4 NAS1 -fstype=nfs4,_netdev,rw,proto=tcp,sync,... xen01.loc:/ a 100MB file xfer takes ~8 minutes 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 (2) Change mount 'sync' -> 'async', 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 the same 100MB file xfer takes ~ 2 seconds 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 ? Is there additional config that cures, or at least drastically improves, this slow down? Some very old (10+ years) posts suggested kernel bugs, but those were fixed ages ago. Maybe reemerged? LT -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
