05-22-2008 04:05 PM - edited 03-05-2019 11:10 PM
I have a 3750. What values do I use for the memory free low-watermark thresholds? Here are the outputs from the show memory:
sand5# sh mem
----------------Head---------Total(b)-------Used(b)-------Free(b)-------Lowest(b)-----Largest(b)
Processor----28B11B4----78966348----33108904----45857444----43916928----43879840
I/O-------------7400000-----12574720-----8637012-------3937708-----3863532-----3935456
cisco WS-C3750G-24T (PowerPC405) processor (revision E0) with 118784K/12280K bytes of memory.
Here are the values from a 6513:
SITSF-Central-Cat#sh mem
----------------Head---------Total(b)-------Used(b)------Free(b)-------Lowest(b)-----Largest(b)
Processor---44D06830---388962256----90744004---298218252---120559528---232898232
I/O--------------8000000----67108864----16487652----50621212-----50621212-----50619484
cisco WS-C6513 (R7000) processor (revision 1.0) with 458720K/65536K bytes of memory
05-29-2008 03:30 PM
pop
memory free low-watermark - threshold is a security feature to protect the memory from DOS.
05-29-2008 05:52 PM
The 3750 shows the "lowest" amount of Processor memory available (presumably since last boot) as 43,916,928 bytes.
Perhaps if you monitor "free" and "lowest" Processor/IO memory over time, you can identify baseline values, then decide how much of a deviation would warrant notification.
The values will change as new features are brought online, and loads increase. So it will warrant periodic re-assessment.
Unfortunately, I think it is up to you to decide how low you wish to allow "free" memory to dip below your baseline before generating a notification.
I set my thresholds a couple MB lower than my baseline. If a notification occurs, I determine how low it went, and try to correlate it to a reason.
I'm doing what makes sense to me without guidance from anyone who might know better.
I'm not sure that there is a "right" answer.
That's all I can offer.
05-30-2008 03:12 PM
www reference:
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gt_memnt.html
Guessing is the only way.
With 78MB of processor memory:
Router(config)# memory free low-watermark processor 10000
This sets the warning threshold to 10MB. i.e. 10%, sort of.
With 12MB of io memory:
Router(config)# memory free low-watermark io 1000
Sets the warning threshold for io to 1000. i.e. 10%
Out of 100MB total, keep a meg reserved for critical operations:
Router# memory reserved critical 1000
i.e. 1% @ 1MB.
memory reserve critical 1000
memory free low-watermark processor 10000
memory free low-watermark IO 1000
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide