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Beginner

RX drops with VNIC 1340

We are running an Oracle RAC database 2 node cluster on Cisco B200M4 / Firmware 3.2(3i)B / enic 2.3.0.53 /  and see RX drops for one VNIC interface. We then have increased RX/TX queues, ring sizes and RSS in Ethernet Policy and will enable MTU 9000 tomorrow. 

 

Still if I test with "iperf" and send packets with > 600 MBit/s over 10GbE interface, i see packet drops (ethtool -S eth1 -> rx_no_bufs).

 

Is this expected? Any idea on how to troubleshoot this further?

 

Regards,

 Martin

 

2 REPLIES 2
Cisco Employee

Re: RX drops with VNIC 1340

This generally indicates that the OS /Process in the OS isn't able to intake the packets fast enough.  RSS, RX ring Size buffers, Interrupts, are the commonly adjusted tunables for your scenario, which it appears you have already adjusted.

https://www.cisco.com/c/dam/en/us/products/collateral/interfaces-modules/unified-computing-system-adapters/vic-tuning-wp.pdf

Is the Baremetal OS, or a vitualized OS running RAC?

You running iperf with the -P and -w (-w 128M) switches?

[edit: use the -P to get parallel streams]

 

 

Kirk...

Beginner

Re: RX drops with VNIC 1340

Hi Kirk,

thank you for your reply.

"-p" is for port. Yes, i have of course set a specific port.
"-w" is for window size/socket buffer size. No, I did not specify "-w".

However, we have specified these kernel parameters:

net.core.rmem_default=4194304
net.core.rmem_max=8388608
net.core.wmem_default=4194304
net.core.wmem_max=8388608
net.ipv4.ipfrag_high_thresh=16777216
net.ipv4.ipfrag_low_thresh=15728640


Regards,
Martin


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