High memory & high CPU issue with 3750 stack switch

[vinayak2010]

Hi,

We are having 3750 Stack switch as our edge switch. Here we are having some issues as low memory & itermediate High CPU utilization.

For memory when we checked its shwoing maximum memory is allocated to DHCPD receive & ARP Input as follows

Processor Pool Total:   70829380 Used:   56809532 Free:   14019848

      I/O Pool Total:   12582912 Used:    8554920 Free:    4027992

Driver te Pool Total:    1048576 Used:         40 Free:    1048536

PID TTY  Allocated      Freed    Holding    Getbufs    Retbufs Process

   0   0   54454548   11892996   38192864          0          0 *Init*

251   0  643329040    5054584    7404360    9128700          0 DHCPD Receive

   9   0 4180150084 1524987760    3031204      26940          0 ARP Input

   0   0 2667113468 3519710580    2550208   12200816    2283560 *Dead*

250   0    4142360    1225500    2504136          0          0 IP RIB Update

209   0  893967348      38072    2444936     443820          0 ADJ resolve proc

318   0  602565616  536479132     629476     147204          0 OSPF-1 Router

  64   0     880872      93976     601628       9612          0 Stack Mgr Notifi

317   0 1140435044 1139876968     562768          0          0 hulc running con

  82   0 1294485012   29072732     549284     205308          0 HLFM address lea

301   0     434144       1300     435508          0          0 CEF: IPv4 proces

173   0   17018872   11222540     395948     308880          0 DTP Protocol

161   0    1625024    1392604     298328          0          0 HL2MCM

160   0     743240     508364     295580          0          0 HL2MCM

  15   0     262124        604     271572      99792          0 EEM ED Syslog

224   0     257764      27812     234612          0          0 MDFS LC Process

186   0    4901740    5517568     209016      65988          0 VMATM Callback

  14   0     486116     294888     200744          0          0 Entity MIB API

i want to understand why this 2 proceses (DHCPD & ARP input) taking more memory?

High CPU: We also facing intermediate high CPU utilization (above 95%). When CPU is high there were 2 processes consuming more CPU are

'Spanning Tree' (about 20%) & ARP Input (about 66%). we also checked the ARP entries, there were 1500 ARP entries & 2 incomplete ARP (out of 6000 ARP supported)

Please help me to understand this issue with ARP & spanning tree processes.

Thanks

[mahmoodmkl]

Hi,

It seems there is a loop in your network and i have seen arp input on this platform consume processor.

Thanks

[vinayak2010]

Hi Mahmood,

thanks for your reply.. is there any relation between Spanning tree & incressing ARP input process?

[mahmoodmkl]

Hi

Does this switch doing routing..?.

Or is there any static route configured pointing to the interface..?

In addition follow the below link for more info.

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_tech_note09186a00807213f5.shtml#topic5.

Thanks

[vinayak2010]

Hi,

yes this switch dose routhing also. As CPU issue is intermediate so might be that coz of network loop as you say.

Do you have any idea about the process DHCPD & ARP Input using high memory?

[mahmoodmkl]

Hi

R u using DHCP on this switch as well.

Thanks

[vinayak2010]

Hi,

No DHCP configured on this switch.