topic Re: FTP speed on blade servers in Operating System - Linux

FTP speed on blade servers

James George_1 — Wed, 21 Nov 2007 09:32:51 GMT

Hi

Iam new in Linux.

This is my problem. We have 9 servers in a blade enclosure , all running Linux , Redhat.
The ftp is very slow between two of these servers. We have 2 subnets invloved here. One of of the servers is on 10.17.3.X and all the other servers on 10.17.13.X . FTP ( 4 GB file) between servers on the same subnet is done in 2 minutes. But from servers on one subnet to the other subnet server, it takes hours !! . WE have involved HP and our n/w team and everything is ok on the n/w side / router / switch side. The Speed setting is also (correct 1GB FULL DUPLEX ) and we don't find any problem.

Now we are doubting the OS side ...Can some one help ?

Rgds/ James

Re: FTP speed on blade servers

Rob Leadbeater — Wed, 21 Nov 2007 09:38:37 GMT

Hi James,

I doubt that this is an OS thing. Sounds more like something in the network to me...

How are the two subnets linked together ?

Cheers,

Rob

P.S. You might want to let people know exactly which version of RedHat you're running just in case...

Re: FTP speed on blade servers

Ivan Ferreira — Wed, 21 Nov 2007 09:49:34 GMT

>>> WE have involved HP and our n/w team and everything is ok on the n/w side / router / switch side.

How did you determine this?

Can you post the output of netstat -ni of both servers?

Have you tried a packet trace/dump, for example, with tcpdump?

Re: FTP speed on blade servers

James George_1 — Wed, 21 Nov 2007 10:49:08 GMT

Here is the version details .

2.6.9-42.0.8.ELsmp #1 SMP Tue Jan 23 12:49:51 EST 2007 x86_64 x86_64 x86_64 GNU/Linux

We even did an ftp from outside the blade to the blade server and it went very well. Looks like it got something to do with the switch inside the Blade Enclosure. But , none of us are good in Linux / blade which is a new arrival in our environment.

Rgds/ JAmes

Re: FTP speed on blade servers

James George_1 — Wed, 21 Nov 2007 10:53:27 GMT

Yes, we did the ( HP) tcpdump . We tried ftp between different servers in and out of the different subnets . The problem is only on this specific server, rest all the servers are transfering data very fast.

rgds/ James

Re: FTP speed on blade servers

James George_1 — Wed, 21 Nov 2007 11:54:23 GMT

Hi Ivan

here is the netstat -in outputs

mixdb01p:/root>netstat -in
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0 1500 0 2743481325 0 0 0 4544026452 0 0 0 BMRU
lo 16436 0 61277474 0 0 0 61277474 0 0 0 LRU

mixdb02d:/root>netstat -in
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth2 1500 0 376081554 0 0 0 785191661 0 0 0 BMRU
lo 16436 0 20926155 0 0 0 20926155 0 0 0 LRU

James

Re: FTP speed on blade servers

Stuart Browne — Wed, 21 Nov 2007 15:39:19 GMT

How big is the subnet mask on each end?

You say you're using different networks, so unless they've got a very large subnet mask, the FTP has to be going through a router somewhere, which means it's probably leaving the blade enclosure and coming back in.

Re: FTP speed on blade servers

James George_1 — Wed, 21 Nov 2007 18:16:06 GMT

The subnet mask are 255.255.255.192 and 255.255.255.128.

You are right, there is cisco 3020 switch , part of the blade .

Rgds/ James

Re: FTP speed on blade servers

Stuart Browne — Wed, 21 Nov 2007 18:50:03 GMT

That's a Layer 2 switch, not a router, so it's leaving the 3020, hitting something outside the enclosure, then coming back in.

Well, that's what I feel from what I've read.

Re: FTP speed on blade servers

Stuart Browne — Wed, 21 Nov 2007 18:51:24 GMT

Forgot to add, 'traceroute' is your friend.

Re: FTP speed on blade servers

James George_1 — Wed, 21 Nov 2007 19:51:30 GMT

traceroute shows 1 hop and its fine.

rgds/ James

Re: FTP speed on blade servers

Stuart Browne — Wed, 21 Nov 2007 22:04:34 GMT

Then there's still some information missing, given they are both on different subnets, and both subnet masks are fairly tight.

Show routing tables on both.

Also show iptbales rules on both (both -t filter and -t nat).

Re: FTP speed on blade servers

Rob Leadbeater — Thu, 22 Nov 2007 04:27:33 GMT

Another thing to consider is that blades tend to have a number of NICs...

Please post the output of

# ifconfig -a
and
# netstat -rn

from a server on each subnet. As others have said, this would appear to be a routing issue.

You've said that Linux is new to you, so it would be useful to see actual output of commands, rather than you just saying the output is "fine".

Cheers,

Rob

Re: FTP speed on blade servers

Matti_Kurkela — Thu, 22 Nov 2007 08:05:07 GMT

With blade servers (at least the new c-series), the speed/duplex state you're seeing with the OS tools (ethtool and the like) will refer to the blade rack's internal wiring only. The internal wiring is forced to 1GB Full Duplex at the hardware level, so it would be surprising if this is incorrect.

To know the speed/duplex settings of the physical outgoing interfaces, you must examine the settings of the enclosure's integrated switch module. If using a pass-through module instead of the integrated switch, the external switch *must* be 1GB Full Duplex capable: the pass-through module is 1GB Full Duplex *only*.

MK

Re: FTP speed on blade servers

Steven E. Protter — Thu, 22 Nov 2007 13:18:50 GMT

Shalom,

If it were all systems on the blade, I'd suspect you outstripped the blades network capacity with demand.

I would suspect in this instance that its a network switch port issue, perhaps duplex is set manually and it should not be.

SEP