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How to Troubleshoot a possible Memory Leak on the NetIron XMR/MLX and MLX-e platforms?

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TitleHow to Troubleshoot a possible Memory Leak on the NetIron XMR/MLX and MLX-e platforms?
Question
In many situations amemory leak is suspected when the available memory in the system (either on the LP or MP) has dropped down to a very low value.

Having low memory does not necessarily mean a memory leak. Legacy MLX LP cards have 512MB of memory and a large configuration with various system max configuration can drive the available memory down to a very low value.

To take several snapshots from the memory values will show us whether we are in a memory leak situation. To determine if there is a memory leak follow the procedure in the Answers section.
Environment
Answer

Follow these steps to debug a potential memory leak:

1)Capture the output of show memory from the NetIron Command promptabout 3 times over the period of a day (about 3-4 hours in between or a couple times a day for a couple days).
2) Capture the output of show memory from the *MP-OSor LP-OS mode multiple times over a period of a few hours, depending on if you are debugging low memory on management module or interface module.
3) If you see that the available memory is continuously decrementing, you can assume there is a memory leak. In order to debug this turn on dtr leakage from the OS mode and let it run for a few hours 4-5 hours.
4)Then gather data using the command sh mem leakage from the OSmode which will potentially show which code is leaking memory.
5)Please forward the captured outputs to Brocade Technical Support to help identify the causeof thepotential memory leak.
6)Turn off dtr leakage by toggling the command from the OS modeprompt.

*Note: (To enter the MP-OSmode you must be on the console (enter rconsole from a Telnet or SSH session to get to console prompt) then enter the following from the command prompt:ctrl and y keys together, then m by itself and then hit enter. To enter the LP-OS, first rconsole x (where x is the slot id forthe applicable LP) and then enter ctrl-y m <enter> )

Note: It is very important to capture memory leak data as the system is leaking memory, in which theHOLD number is going up steadily from the sh mem command taken from the OSmode. Capturing this data when the system has already leaked most of its memory or the HOLD value is not going up steadily will not yield any useful data. Continuously run a script to capture this sh mem output during the time that the dtr leakage is enabled.

Examples:

MP:
telnet@Router1# rconsole
Remote connection to MP local port established
Press CTRL-X or type 'exit' to disconnect it
Router1>en
No password has been assigned yet...
Router1# <ctrl-y, then m, then enter>
MP-1 OS> dtr leakage (toggle to turn off/on)
Memory trace started
MP-1 OS> dtr leakage(toggle to turn off/on)
Memory trace stopped


LP:
telnet@Router1# rconsole 3
Remote connection to LP slot 3 established
Press CTRL-X or type 'exit' to disconnect it
LP-3# <ctrl-y, then m, then enter>
LP-3 OS> dtr leakage
Memory trace started
LP-3 OS> dtr leakage
Memory trace stopped


LPsh mem from LP-OS:
LP-3 OS> show mem
ID Memory Used Available Success Hold Fail Error
0 9474048 57368576 608413 96 0 0 OS
2 124268544 556093440 62452712 7643 0 0 Global
<<<<< HOLD value is the most important data
- 40964096 26144768 7 7 0 0 DMA
Total Installed: 1073741824, Total Free: 556097536
<<<<<<This LP has 1 GB memory installed (the bold number)

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