Re: Sudden deterioration of network speed

From: tjchamp (tjchamp_at_qwest.net)
Date: 08/11/04 

Date: 11 Aug 2004 07:42:57 -0700

original_brownster@yahoo.co.uk (Wayne) wrote in message news:<bdabe300.0408110139.3e6402ba@posting.google.com>...
> We have 2 RS6000's running AIX 4.3, there is a nightly copy of the
> data; using rcp; from one to the other for various purposes. Both
> box's have 100Mb cards and they are connected via a switch on a 100Mb
> lan.
> We write away the size of the data and the start/ end time of the
> process as part of the script I have written so I know it has always
> taken around 4 hours to complete the copy; the amount of data is 23GB.
> Recently, the copy started to take 8.5 hours to complete so we started
> investigating the cause and the only thing that has changed(and on the
> same day that the problem began) is we have added 4 Citrix servers
> connected via a gigabyte switch, this in turn is connected via an
> uplink cable to our normal 100Mb lan. They are unused at present apart
> from around 10 people in the IT dept who are testing it through the
> daytime and at anyrate shouldn't create any traffic at night.
>
> Based on the data being copied I calculated that we would have been
> achieving a data transfer rate of approx. 1,500KB per second and that
> now it has dropped to 880KB per second; does 1,500KB sound
> achievable?
>
> I used smit to run diagnostics on both the network card and the
> mirrored disks where the data is stored and it reported no problems.
> We powered down the Citrix servers and (unsuprisingly perhaps) it made
> no difference.
> Below I have posted the output of 'netstat -v' for each server
>
> Any help / ideas please?
>
> Wayne.
>
> --------------------------------------------------------------------------------
> Live Server NIC stats: (server that data is copied from)
>
> ETHERNET STATISTICS (ent0) :
> Device Type: DEC 21x4x PCI Ethernet Controller
> Hardware Address: 00:00:c0:19:5c:fd
> Elapsed Time: 143 days 18 hours 3 minutes 25 seconds
>
> Transmit Statistics: Receive Statistics:
> -------------------- -------------------
> Packets: 2247780361 Packets: 1132035070
> Bytes: 3205988176986 Bytes: 69479696920
> Interrupts: 3 Interrupts: 705996514
> Transmit Errors: 0 Receive Errors: 22
> Packets Dropped: 0 Packets Dropped: 0
> Bad Packets: 0
> Max Packets on S/W Transmit Queue: 0
> S/W Transmit Queue Overflow: 0
> Current S/W+H/W Transmit Queue Length: 1
>
> Broadcast Packets: 6394 Broadcast Packets:
> 20019936
> Multicast Packets: 2 Multicast Packets: 10
> No Carrier Sense: 0 CRC Errors: 22
> DMA Underrun: 0 DMA Overrun: 0
> Lost CTS Errors: 0 Alignment Errors: 1
> Max Collision Errors: 0 No Resource Errors: 0
> Late Collision Errors: 0 Receive Collision
> Errors: 0
> Deferred: 0 Packet Too Short Errors:
> 0
> SQE Test: 0 Packet Too Long Errors:
> 0
> Timeout Errors: 0 Packets Discarded by
> Adapter: 0
> Single Collision Count: 0 Receiver Start Count: 2
> Multiple Collision Count: 0
> Current HW Transmit Queue Length: 1
>
> General Statistics:
> -------------------
> No mbuf Errors: 0
> Adapter Reset Count: 0
> Driver Flags: Up Broadcast Running
> Simplex AlternateAddress 64BitSupport
>
> DEC 21x4x PCI Ethernet Controller Specific Statistics:
> -----------------------------------------------------
> Device ID: 21140
> Interface type supported: 10 BaseT
> 10 BaseT Full Duplex
> 100 BaseTX
> 100 BaseTX Full Duplex
> Auto Sensing capability: NO
> Auto Negotiation capability: YES
>
> Media Speed Running: 100 Mbps Full Duplex
> Link Partner Negotiable: YES
> Media Speed Selected: Auto Detection
> Adapter Restarts due to IOCTL commands: 0
> -------------------------------------------------------------
>
>
> ********************************************************************************
> --------------------------------------------------------------------------------
> DW Server NIC stats: (server that data is copied to)
>
> ETHERNET STATISTICS (ent0) :
> Device Type: IBM 10/100 Mbps Ethernet PCI Adapter (23100020)
> Hardware Address: 00:02:55:76:b3:00
> Elapsed Time: 0 days 18 hours 39 minutes 34 seconds
>
> Transmit Statistics: Receive Statistics:
> -------------------- -------------------
> Packets: 8185572 Packets: 16492456
> Bytes: 498346049 Bytes: 23941454331
> Interrupts: 50 Interrupts: 16491574
> Transmit Errors: 0 Receive Errors: 0
> Packets Dropped: 0 Packets Dropped: 0
> Bad Packets: 0
> Max Packets on S/W Transmit Queue: 27
> S/W Transmit Queue Overflow: 0
> Current S/W+H/W Transmit Queue Length: 1
>
> Broadcast Packets: 1141 Broadcast Packets:
> 125298
> Multicast Packets: 0 Multicast Packets: 0
> No Carrier Sense: 0 CRC Errors: 0
> DMA Underrun: 0 DMA Overrun: 0
> Lost CTS Errors: 0 Alignment Errors: 0
> Max Collision Errors: 0 No Resource Errors: 0
> Late Collision Errors: 0 Receive Collision
> Errors: 0
> Deferred: 0 Packet Too Short Errors:
> 0
> SQE Test: 0 Packet Too Long Errors:
> 0
> Timeout Errors: 0 Packets Discarded by
> Adapter: 0
> Single Collision Count: 0 Receiver Start Count: 0
> Multiple Collision Count: 0
> Current HW Transmit Queue Length: 1
>
> General Statistics:
> -------------------
> No mbuf Errors: 0
> Adapter Reset Count: 0
> Adapter Data Rate: 200
> Driver Flags: Up Broadcast Running
> Simplex AlternateAddress 64BitSupport
> PrivateSegment DataRateSet
>
> IBM 10/100 Mbps Ethernet PCI Adapter Specific Statistics:
> ------------------------------------------------
> Chip Version: 26
> RJ45 Port Link Status : up
> Media Speed Selected: Auto negotiation
> Media Speed Running: 100 Mbps Full Duplex
> Receive Pool Buffer Size: 384
> Free Receive Pool Buffers: 128
> No Receive Pool Buffer Errors: 0
> Inter Packet Gap: 96
> Adapter Restarts due to IOCTL commands: 0
> Packets with Transmit collisions:
> 1 collisions: 0 6 collisions: 0 11 collisions: 0
> 2 collisions: 0 7 collisions: 0 12 collisions: 0
> 3 collisions: 0 8 collisions: 0 13 collisions: 0
> 4 collisions: 0 9 collisions: 0 14 collisions: 0
> 5 collisions: 0 10 collisions: 0 15 collisions: 0
> Excessive deferral errors: 0x0

Notice the CRC errors on the first server. Turn off auto detect and
hard code the card for 100 full duplex.

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