Re: 2.4.21, NFS v3, and 3com 920

[Samuel Flory <sflory@rackable.com>]

Valdis.Kletnieks@vt.edu wrote:

>On Tue, 22 Jul 2003 00:42:45 CDT, Matthew Hunter <matthew@infodancer.org>  said:
>
>  
>
>>Running more tests, it turns out the speed problem is isolated to 
>>the one machine, and only to *receiving* data.  Sending goes at 
>>8 M/s to other machines from the client machine.  Sending from 
>>any machine to the client machine is slowed down, not just from 
>>the server.
>>    
>>
>
>These symptoms sound suspiciously like a 100BaseT auto-negotiation
>problem.  With some combinations of gear, if one end is set to auto-negotiate
>and the other end is nailed to full/half duplex (sorry, can't remember which and
>I've not my caffiene yet), things go horribly wrong and many packets
>dissapear silently on transmission, forcing retransmit timeouts and bad
>throughput.  Basically, you end up with one end thinking it's full duplex,
>the other end at half - and if the full duplex side ever sends a packet while
>the half side is sending, the packet's lost.
>
>Try nailing the devices on both ends of the cat-5 to the same thing (full or
>half).  This can of course be interesting if you have an unmanaged hub that
>doesn't give you a choice...
>
>
>
>  
>

  You should be able to use mii-tool, or ethtool (one or both should 
work) to check the state your ethernet controller thinks it is set to, 
and change the settings.

[root@sflory cujo]# mii-tool -v eth0
eth0: negotiated 100baseTx-FD, link ok
  product info: vendor 00:aa:00, model 51 rev 0
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
  link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
[root@sflory cujo]# ethtool eth0
Settings for eth0:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: puag
        Wake-on: g
        Link detected: yes
[root@sflory cujo]#

-- 
Once you have their hardware. Never give it back.
(The First Rule of Hardware Acquisition)
Sam Flory  <sflory@rackable.com>