Re: tcp ethernet RX overrun

  • From: Riyaj Shamsudeen <riyaj.shamsudeen@xxxxxxxxx>
  • To: dbaprimatics@xxxxxxxxx
  • Date: Tue, 22 May 2012 13:56:54 -0500

Hello Vamshi
   You can't completely eliminate dropped packets. There will be drops and
errors due to issues in the host and outside the host. In your case, 3
million packets are dropped out of 91 Billion packets received, merely
0.0033%. I doubt, this is an issue.

    But, if you are in Linux platform, use ethtool -S eth4 to see where the
failures occurred.

    What problem are you trying to solve?

Cheers

Riyaj Shamsudeen
Principal DBA,
Ora!nternals -  http://www.orainternals.com - Specialists in Performance,
RAC and EBS
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On Tue, May 22, 2012 at 1:21 PM, Vamshi Damidi <dbaprimatics@xxxxxxxxx>wrote:

> To all network masters:
> Can you please throw some light on how to debug ethernet errors and
> overruns.
> below is network interface.
>
> eth4      Link encap:Ethernet  HWaddr 00:10:18:98:D7:18
>          inet6 addr: fe80::210:18ff:fe98:d718/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:91675115854 errors:3057985 dropped:0 overruns:3057245
> frame:740
>          TX packets:20876846657 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:118442063462040 (107.7 TiB)  TX bytes:21442788961564
> (19.5 TiB)
>          Interrupt:40 Memory:dc800000-dcffffff
>
> We are using 10G broadcom dual nics with tcp buffersize
> #SCSI TCP buffer fix
> net.core.rmem_max = 1073741824
> net.core.wmem_max = 1073741824
> net.ipv4.tcp_rmem = 1048576 16777216 1073741824
> net.ipv4.tcp_wmem = 1048576 16770216 1073741824
> net.ipv4.tcp_mem = 1048576 16770216 1073741824
>
> and iscsi config as below.
>
> node.startup = automatic
> node.session.timeo.replacement_timeout = 120
> node.conn[0].timeo.login_timeout = 15
> node.conn[0].timeo.logout_timeout = 15
> node.conn[0].timeo.noop_out_interval = 10
> node.conn[0].timeo.noop_out_timeout = 15
> node.session.initial_login_retry_max = 4
> node.session.cmds_max = 128
> node.session.queue_depth = 128
> node.session.iscsi.InitialR2T = No
> node.session.iscsi.ImmediateData = Yes
> node.session.iscsi.FirstBurstLength = 16776192
> node.session.iscsi.MaxBurstLength = 16776192
> # the default is 131072
> node.conn[0].iscsi.MaxRecvDataSegmentLength = 16776192
> # the default is 32768
> discovery.sendtargets.iscsi.MaxRecvDataSegmentLength =  16776192
> node.conn[0].iscsi.HeaderDigest = None
> node.session.iscsi.FastAbort = No
>
>
> Thanks,
> Vamshi .D
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>


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