AIX Slow Networking

[geekpro]

Hi Everybody,

I'm new to AIX and I'm having a big problem with slow networking performance.
Using FTP or SCP in a 100Mbps/Ethernet network, I only gets transfers of aprox. 85KBps!

Anyone knows how to fix this?

Tks!

Herbert

 

[Yegolev]

Check adapter settings in `smit ethernet`. AIX does not like auto_negotiate. IBM Certified -- AIX 4.3 Obfuscation

 

[geekpro]

I was unable to find this option on smit... Can you help me?

 

[aixqueen]

smit devices
communication
ethernet adapter
change speed and change to database only to yes...
Unless you are going to do an ifconfig en0 down, ifconfig en0 detach
then go in and change the speed........ then bring card up.

If you do to database only it will be changed on next reboot...

Make sure both sides are set to the same level

---------------
entstat -d ent0
Is the card status up?
if not do a chdev -l en0 -a state=up
netstat -d ent1
netstat -v | egrep "STATISTICS|Media Speed"

ETHERNET STATISTICS (ent1)
Media Speed Selected: Auto negotiation
Media Speed Running: 10 Mbps Half Duplex
The first is how it is set up, the second is the speed it is using.


lsattr -E -l en0
------------------------
ftp you had to have patches on...make sure you are at latest...
also on ftp

TUNING For FTP performance:

Make sure that the ethernet card is set up correctly. If you are doing full
duplex, make sure both sides are on full. Both sides set for the same
speed...100/100 etc....

Then The key parameter is the "tcp_mssdflt" setting which the TCP/IP
protocol uses as a starting point for negotiating a packet size from the txnode
to the rx node. This MUST be less than the tcp_sendspace and less than the
MTU size. Start with the 32768 value and decrease it incrementally until your
FTP streaming occurs.

thewall Specifies the maximum amount of memory, in kilobytes, that is
allocated to the memory pool. In AIX Version 4.2.1 and earlier, the default
value is 1/8 of real memory or 65536 (64 megabytes), whichever is smaller. In
AIX Version 4.3, the default value is 1/8 of real memory or 131072 (128
megabytes), whichever is smaller. In AIX Version 4.3.1, the default value is
1/2 of real memory or 131072 (128 megabytes), whichever is smaller. In AIX
Version 4.3.2 and later, the default value is 1/2 of real memory or 1048576 (1
gigabyte), whichever is smaller. thewall is a runtime attribute.

no -o thewall=131072 (or whatever we decide to use) (if yours is higher...leave
it alone..it should be ok)

http://publib.boulder.ibm.com/doc_link/en_US/a_doc_lib/aixbman/prftungd/2365ch9.htm#23142

Use with caution........and remember what you had your setting at before messing with them... and make sure you have a good mksysb if all else fails....

 

[AIXSPadmin]

smitty
devices
communication
ethernet adapter
adapter
change/show characteristics of an ethernet adapter
[select adapter ent0/ent1/ent???]
Media Speed [change to 100 full duplex]

 

[geekpro]

Unfortunately the network device is already set to 100/Full Duplex.

Any other suggestion?

 

[AIXSPadmin]

Maximum IP packet size for the network interface. Same smit panels except use services instead of adapter, then change/show, select adapter.

 

[geekpro]

It's already on 1500... the same on the other servers....

I've had a good network perfomance, mounting a NFS share
from this AIX server on a Linux server and copying on it.
I think now that is something related to TCP on this AIX server. UDP is doing well.

 

[mkharris]

A colleague of mine hit something similar yesterday. He'd just updated to ML10, and the IP performance went into a dive. He reinstalled to get back to ML09 again, and everything was back to normal. Tried another update to ML10, and the same problem happened again. What ML are you running?

 

[geekpro]

Humm... This can be the solution, but... I don't know what is ML and where can I see it's version. Can you explain me?

 

[AIXSPadmin]

Try these commands to get your maint level:
oslevel -r -q
instfix -i | grep AIX_ML

shown below they return:
(x974)/var/adm/SPlogs/sysman#oslevel -r -q
Known Recommended Maintenance Levels
------------------------------------
4330-09
4330-08
4330-07
4330-06
4330-05
4330-04
4330-03
4330-02
4330-01
4320-02
(x974)/var/adm/SPlogs/sysman#instfix -i | grep AIX_ML
All filesets for 4.3.1.0_AIX_ML were found.
All filesets for 4.3.2.0_AIX_ML were found.
All filesets for 4.3.1.0_AIX_ML were found.
All filesets for 4.3.2.0_AIX_ML were found.
All filesets for 4.3.3.0_AIX_ML were found.
Not all filesets for 4330-02_AIX_ML were found.
All filesets for 4320-02_AIX_ML were found.
Not all filesets for 4330-03_AIX_ML were found.
Not all filesets for 4330-04_AIX_ML were found.
Not all filesets for 4330-05_AIX_ML were found.
Not all filesets for 4330-01_AIX_ML were found.
Not all filesets for 4330-06_AIX_ML were found.
Not all filesets for 4330-07_AIX_ML were found.
Not all filesets for 4330-08_AIX_ML were found.
Not all filesets for 4330-09_AIX_ML were found.

 

[geekpro]

I've got this results.... How can I upgrade to ML10?

# oslevel -q
Known Maintenance Levels
------------------------
4.3.3.0
4.3.2.0
4.3.1.0

# instfix -i | grep AIX_ML
All filesets for 4.3.1.0_AIX_ML were found.
All filesets for 4.3.2.0_AIX_ML were found.
All filesets for 4.3.1.0_AIX_ML were found.
All filesets for 4.3.2.0_AIX_ML were found.
All filesets for 4.3.3.0_AIX_ML were found.
All filesets for 4330-02_AIX_ML were found.
Not all filesets for 4320-02_AIX_ML were found.
All filesets for 4330-03_AIX_ML were found.
All filesets for 4330-04_AIX_ML were found.

 

[Chapter11]

A guess: network options, mtu discovery.

Do "no -a | grep _pmtu_discover", you should get a line for TCP and UDP.

Mine are currently set to 0 (off). I recall having an issue recently where a 4.3.3 maintenance level change changed this setting (to 1, on), and it borked my network connectivity. Manually changing it back to 0 fixed the problem. It's been too long for me to remember the specifics though.

 

[mkharris]

My previous post was to warn that Maintenance Level 10 might be faulty. This should be ignored. The problem we experienced has since proved to be a network issue that the new ML exposed!

Chapter11 gave better advice, so I'd be inclined to go with that.

Maintenance levels can be downloaded from the IBM support site, but ML10 is fairly large.

 

[geekpro]

I've set tcp_pmtu_discover to 0 and nothing changed... Need I to reset the server to use this setting?

mkharris... that's ok... I haven't done nothing with ML...
Thanks anyway!

I'm still lost on what's happening whith this AIX... :-(

 

[Chapter11]

As far as I know, the *_mtu_discovery options change dynamically, I don't believe you should need to reboot for them to take effect, in fact, you might want to include them in a local startup script.

 

[geekpro]

Ok...
I'm still having the problem...
Please.... someone share your solutions...
It's a life-or-dead case for me and for AIX in the company I works for...

 

[Chapter11]

Try another port on your hub/switch? Try another port on your 6k (if you have one)? Try 100/half duplex? (make sure both the switch and the 6k are set the same). Try another ethernet cable?

 

[Yegolev]

Maybe bad adapter, too, anything in errpt? I'd say check cable last unless you know of some reason it might have been damaged. Also might be the switch port. IBM Certified -- AIX 4.3 Obfuscation

 

[fluffybunny]

You might want to try using diag and do a probe of your network, network adapter, etc or even a diag on your network settings. Sometimes it helps.

Cheers.