Slow FTP

[Tim Killinger]

Our new completely unloaded rp5450/UX11.0 has extremely slow FTP transfer rates between both windows PCs and VMS servers on the same local network segment. Tansfer rates between a PC and the VMS host or PC to PC are quick, so it's something with the UX box.

Any suggestions? Any IP stack tuning that might be necessary? UX and UNIX is new to us, so we're not sure where to start.

[harry d brown jr]

Things to look for:

On the HP Server side check:
(1) duplex - usually full
(2) speed of card
(3) routing
(4) DNS
(5) security settings
(6) routers /+ switches
(7) traffic on subnet

live free or die
harry

[Darrell Allen]

I'd bet on the duplex settings not negiotiating properly between the server and the switch port. This is a notorius problem.

I always force the speed and duplex setting on the switch port and the server NIC.

Darrell

[Steven E. Protter]

If there is a router in the mix, check that.

From the unix side

traceroute remote_ip


from the windows workstation

tracert hp_server_ip

Long hop times means bottlenecks.

[A. Clay Stephenson]

I would just about bet the bank on this being a duplex issue. It is essential that you hard-set the speed/duplex values on both the UNIX host and on the corresponding switch ports.

With mismatched duplex setting, telnet sessions and pings can appear normal but anything with heavy traffic (like FTP) will be a dog.

[Ron Kinner]

To prove it's a DUPLEX mismatch simply transfer a big file both ways (get it and then put it back). One direction will work a lot faster than the other.

Ron

[Tim Killinger]

Where do I check/set duplex settings and speed on the NIC?

I'm also going to verify the CAT 5 drop to the hub and have network support check the settings on the hub.

It took 6 hours to transfer a 330mb file...it transfered, but jeez! :)

Thanks!

[Pete Randall]

lanadmin -x 0

(where 0 is the card's instance number - from lanscan)

will show you the speed/duplex settings of the NIC.

Pete

[Berlene Herren]

You can also test by ftp-ing a large file to /dev/null, or by using the tool NETPERF, created by our own Rick Jones.

See http://www.netperf.org/

Berlene

[rick jones · Accepted solution]

netperf can be useful - particularly since it allows you to eliminate disc bottlenecks from the equation.

HP-UX 100BT NICs default to auto negotiation. I myself have had considerable success with autoneg with HP NICs and ProCurves, and some Alteons and Ciscos.

If "autoneg" fails, the IEEE spec says that the autoneging end must go into half-duplex.

Autoneg will fail if the switch vendor botched it (in this day and age that shouldn't be happening) or if the network admin hardcoded the switch port.

Anyhow, if there is a duplex mismatch, lanadmin -g mibstats will show (in the interface description - one of the first lines) if the NIC is in half or full. If in half, look for _late_ collisions - that will indicate (if you are connected to a switch rather than a hub) that there is a duplex mismatch. If the NIC is in full duplex, the stat that will indicate mismatch with the switch will be FCS errors.

If you have neither FCS errors or _late_ collisions, you do not have a duplex mismatch.

Other things that will be seen with a duplex mismatch would be TCP retransmissions (netstat -p tcp) on the sending side, and out-of-order receives on the receiving side. Of course there can be many other reasons for those besides duplex settings :)

[Greg OBarr]

I had the same problem. In my case, I noticed that when copying a file, it seemed to start quickly and then slow down drastically. The problem would only occur between 2 HP-UX systems, not from a PC to the HP-UX server. The problem turned out to be that the 2 HP-UX systems, when talking to each other, were using large frame sizes. Even thought the MTU for the lan0 interface was configured at 1500, it seemed to be using the MTU of 4136, like on lo0 (netstat -i). Setting JUMBO FRAMES on our Cisco switch for the ports connected to the HP-UX servers solved the problem for me.

[John Meissner]

When I have slow ftp's I usually check to make sure that duplex is set to
autonegotiate: off
duplex: full
check to make sure the card is a 100 base or faster. is DNS pointing to the wrong address (wrong card) on the server that might be slower? File size should also be taken into consideration. Bandwidth between the two computers (there may be a lot of hops or a slow router somewhere in your path)