[SNMP4J] diskIOWrites - cached responses

[George Chelidze]

Hello,

I have recently posted this question on Suns Developer Forums "General - 
Maintenance" mailing list (original post: 
http://forum.java.sun.com/thread.jspa?threadID=5241082&tstart=0) but 
didn't received any response yet. First I thought it was sun related 
problem, however after some investigation is seems to be snmp related. 
That's why I decided to post here:

OS: SunOS 5.10 Generic_118833-24 sun4u sparc SUNW,Sun-Fire-880
NET-SNMP version:  5.0.9

I am trying to monitor diskIOWrites. The problem I am faced with is that 
snmpget seems to "cache" responses for the above mentioned object. I 
have made the following test:

-bash-3.00$ while true; do snmpget -v 1 -c public localhost 
diskIOWrites.5; sleep 1; done
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721780814
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721782866
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721784886
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721787012
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721787012
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721787012
UCD-DISKIO-MIB::diskIOWrites.5 = Counter32: 721787012
^C
-bash-3.00$

as you can see, new value is returned after ~10th request is sent. The 
situation is similar on another partition:

-bash-3.00$ while true; do snmpget -v 1 -c public localhost 
diskIOWrites.1; sleep 1; done
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776583902
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776583902
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776583902
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776584631
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776584631
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776584631
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776584631
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776584631
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776585793
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776585793
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776585793
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776585793
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776586767
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776586767
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776586767
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776586767
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776586767
UCD-DISKIO-MIB::diskIOWrites.1 = Counter32: 776587949
^C
-bash-3.00$

however, new value is returned every ~5th request.

Is there any option to snmpd/OS/anything to disable this "caching" and 
where can I get more information on this topic. Thanks in advance.

Best Regards,

George Chelidze