IP fragmentation fails and fragmented packets get dropped
Issue
- We have a three node Oracle RAC and this morning we had problem with one node. When we reviewed the historic
netstat -souput we noticed that the following counter spiked around that time.
54672220 packet reassembles failed
- After that event the module could not be pinged with a packet size greater than the MTU.
# ping <IP Addr> -s 1600
Environment
- Red Hat Enterprise Linux 6.6 (
kernel-2.6.32-504.el6) and later - Red Hat Enterprise Linux 6.7.z (
kernel-2.6.32-573.7.1.el6) and earlier - Oracle RAC or other application which commonly sends IP fragments
- IP fragmentation
- Systems with many CPU cores
- In one instance, the system had 160 CPU cores
- Sytemss with smaller amounts of CPUs are not affected.
- For example, we could not reproduce this on a machine with 12 CPU cores
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