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New Member

3750G Stack performance issues.

I have a 3 Switch 3750G stack that is experiencing some network transfer speed issues.  I have a bunch of users that transfer large amounts of data to and froma server if the user is plugged into the same switch the server is plugged into then get the transfer speed I would expect at 70 to 100 MBps if the are on one of the other switches in the stack their transfer speed is terrible at 2MBps to 6MBps.  This Stack does not provide any layer 3 routing and the traffic is on the same VLAN.

This has been an ongoing problem and I need to get this fixed.

Switch Ports Model              SW Version            SW Image                

------ ----- -----              ----------            ----------              

*    1 28    WS-C3750G-24PS     15.0(2)SE2            C3750-IPBASEK9-M        

     2 28    WS-C3750G-24PS     15.0(2)SE2            C3750-IPBASEK9-M        

     3 28    WS-C3750G-24PS     15.0(2)SE2            C3750-IPBASEK9-M       

sh switch stack-ring speed

Stack Ring Speed        : 32G
Stack Ring Configuration: Full
Stack Ring Protocol     : StackWise

sh switch stack-ports
  Switch #    Port 1       Port 2
  --------    ------       ------
    1           Ok           Ok  
    2           Ok           Ok  
    3           Ok           Ok  

sh switch stack-ports sum

Switch#/  Stack   Neighbor   Cable    Link   Link   Sync      #         In 
Port#     Port              Length    OK   Active   OK    Changes   Loopback
          Status                                          To LinkOK         
--------  ------  --------  --------  ----  ------  ----  ---------  --------
  1/1     OK         2      50 cm     Yes    Yes    Yes        1        No
  1/2     OK         3      50 cm     Yes    Yes    Yes        1        No
  2/1     OK         3      50 cm     Yes    Yes    Yes        1        No
  2/2     OK         1      50 cm     Yes    Yes    Yes        1        No
  3/1     OK         1      50 cm     Yes    Yes    Yes        1        No
  3/2     OK         2      50 cm     Yes    Yes    Yes        1        No

Average CPU is 7%

Memory Used is 72%

TIA

Everyone's tags (4)
2 ACCEPTED SOLUTIONS

Accepted Solutions
Super Bronze

Re: 3750G Stack performance issues.

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Well that's curious.

Unsure whether you're using a "solid" IOS version.  If you don't need some of the newer IOS features, you might consider downgrading to (55)SE8.  ("Leo" might see this and offer a good recommendation for newer IOS too.)

One issue with StackWise, all traffic on all switch ports is flooded to the stack ring, and is removed by sending switch.  I.e. if you have lots of busy ports, you might be overloading the ring.  (The original 3750 series was really oriented toward less active user ports, rather than more active server ports. The later StackWisePlus, that first came with the 3750E series, is much superior.)

I recall there's a command to check ring utilization, but don't recall what it is, specifically, or whether it applies to the earlier 3750 series.  If you find it, check your ring utilization.

If QoS is enabled, and you don't need QoS features, disable it.

If your sever is on a copper port, and that port shows drops, you can also move it one of your SFP ports (will require copper SFP), as they might get more RAM buffers, per port group.

Hall of Fame Super Gold

3750G Stack performance issues.

I recall there's a command to check ring utilization, but don't recall what it is, specifically, or whether it applies to the earlier 3750 series.

I seldom check the ring utilization.  Instead I check the switch's real-time port utilization using the command "sh controller util".  The values are expressed in "%".

Unsure whether you're using a "solid" IOS version.  If you don't need some of the newer IOS features, you might consider downgrading to (55)SE8.  ("Leo" might see this and offer a good recommendation for newer IOS too.)

IOS currently being used by the OP, 15.0(2)SE2, is a well-known CPU hog.  I wouldn't touch it even if I was paid. 

And I agree, good stable IOS for 3750/G/E/X is either 12.2(55)SE8 or 15.0(2)SE4. 

7 REPLIES
Super Bronze

Re: 3750G Stack performance issues.

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Well that's curious.

Unsure whether you're using a "solid" IOS version.  If you don't need some of the newer IOS features, you might consider downgrading to (55)SE8.  ("Leo" might see this and offer a good recommendation for newer IOS too.)

One issue with StackWise, all traffic on all switch ports is flooded to the stack ring, and is removed by sending switch.  I.e. if you have lots of busy ports, you might be overloading the ring.  (The original 3750 series was really oriented toward less active user ports, rather than more active server ports. The later StackWisePlus, that first came with the 3750E series, is much superior.)

I recall there's a command to check ring utilization, but don't recall what it is, specifically, or whether it applies to the earlier 3750 series.  If you find it, check your ring utilization.

If QoS is enabled, and you don't need QoS features, disable it.

If your sever is on a copper port, and that port shows drops, you can also move it one of your SFP ports (will require copper SFP), as they might get more RAM buffers, per port group.

Hall of Fame Super Gold

3750G Stack performance issues.

I recall there's a command to check ring utilization, but don't recall what it is, specifically, or whether it applies to the earlier 3750 series.

I seldom check the ring utilization.  Instead I check the switch's real-time port utilization using the command "sh controller util".  The values are expressed in "%".

Unsure whether you're using a "solid" IOS version.  If you don't need some of the newer IOS features, you might consider downgrading to (55)SE8.  ("Leo" might see this and offer a good recommendation for newer IOS too.)

IOS currently being used by the OP, 15.0(2)SE2, is a well-known CPU hog.  I wouldn't touch it even if I was paid. 

And I agree, good stable IOS for 3750/G/E/X is either 12.2(55)SE8 or 15.0(2)SE4. 

New Member

3750G Stack performance issues.

Leo 

Would you conside 15.0(2)SE4 and better choice over 15.0(2)SE5?

That is goo to know about SE2 I will check the rest of my switches now.

Hall of Fame Super Gold

3750G Stack performance issues.

Would you conside 15.0(2)SE4 and better choice over 15.0(2)SE5

SE4 is far better than SE5 by a mile!

Tested SE5 very quickly:  Loaded the IOS, loaded the config.  Saw Tracebacks.  End of testing.  SE5 fails. 

Hall of Fame Super Gold

3750G Stack performance issues.

Would you conside 15.0(2)SE4 and better choice over 15.0(2)SE5

And don't even bother thinking about using 15.2(1)E or 15.2(1)E1 unless you want to break down into tears.

New Member

3750G Stack performance issues.

I've seen the tracebacks on my switch and wansn't sure what to do with them and havent had time to look.  Good to know.

I will try this out.

Super Bronze

Re: 3750G Stack performance issues.

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

Tracebacks usually means software bugs.

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