I have a device that sends out information at 4.7 Megabytes a second. I have a desktop that receives the data from this device that runs Red Hat Enterprise Linux 5.5. They are on the same switch, a 24-port Juniper EX2200.
When I write the data to the desktop on the local filesystem, there's no dropped information. When I write the data to an NFS share, the device reports dropped packets. I have tried playing with the rsize/wsize NFS parameters (8192K seems to be the best value), and values in /proc/sys/net/core/{r,w}mem_{default,max} and increasing the NFS daemon count, as suggested by http://nfs.sourceforge.net/nfs-howto/ar01s05.html. Very similar results across the board. The NFS server also runs RHEL5.5. It's got 11 600gb 15k SAS drives in a hardware RAID6 array. Running 'iftop' on the machine during the data gathering operations, I'll see bursty traffic... that is to say, workstation -> NFS server traffic will be in the high 40mb/sec rate, then slow down, and once it slows down the device I refer to complains of dropped information then it'll speed up again. I find it hard to believe that a machine on the same (recent, gigabit) switch can't write out 4.7MB/sec. Am I wrong? Does anyone have any NFS or TCP tuning recommendations that may be a little more up to date than the NFS howto that was last updated in 2006? I'm really at a loss here. Thank you, more than a lot, in advance.. - Pat _______________________________________________ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/