Description

This article provides insight on sheaf memory and the related log message it populates on the EX series Switch.

Symptoms

The occurrence of log messages related to sheaf memory need not always indicate the presence of a memory leak.  This is validated through the example in this article

Solution

 

Sheaf memory deals with the transfer of control and data packets between theRrouting Engine (RE) and the Packet Forwarding Engine (PFE). The sheaf background thread checks periodically for leaks to make sure the allocation of memory is not going beyond six times the maximum entries. On the EX Switch we will come across following logs :

fpc0 SHEAF: %PFE-3: possible leak, ID 5 (packet(100)) (405/10/40)
fpc0 SHEAF: %PFE-3: possible leak, ID 5 (packet(100)) (405/10/40)
fpc0 SHEAF: %PFE-3: possible leak, ID 5 (packet(100)) (405/10/40)
fpc0 SHEAF: %PFE-3: possible leak, ID 5 (packet(100)) (405/10/40)
The occurrence of this message doesn't necessarily indicate the presence of a memory leak. The message is a representation of a spike due to excess traffic. We see the above leak message reoccurs after 60 seconds where we see the Sheaf ID, the name, (total allocated, minimum, maximum). Here the total allocated is 10 times higher than the max value. Here a function will syslog an alert once we go 6 times higher than the maximum value set. if the error stops over sometime then certainly we have no leak.