His's questions

I have asked the following questions on StackOverflow, but haven't received a single answer yet, presumably because no one there seems to be knowledgable enough about SNMP and my questions. So, I am asking on ServerFault now, hoping someone could help me since this is also related to networking.

I am new to SNMP and have troubles understanding the SNMP requirements of a Java application I am required to implement. I am using openDMK to provide the SNMP support. Please excuse any brutal ignorance in my questions. I have read the RFC specs, but most of the text appear to be gibberish to me.

One requirement is that "SNMP support must be comformable with Alarm MIB (RFC 3877)".

• What does this mean?
• What is Alarm MIB used for?
• Is this related to SNMP Trap/Notification? Reading the RFC specs, I have the feeling that this is about the SNMP Notification/Trap that my application needs to send out to the managers in case something bad occurs (e.g. a threshold was exceeded). If so, I still don't understand what exactly I need to do with this requirement.
  • I will need to define my own application's SNMP Trap definitions (i.e. not using the generic ones). How will my MIB be different now that I need to support Alarm MIB?
  • Is it that, besides sending out a Notification, I need to store that Notification in the Alarm table? If so, what is the purpose of doing so?

• Below is a method from the openDMK library to send out a SNMPv2 Trap:

  public void snmpV2Trap(SnmpOid trapOid, SnmpVarBindList varBindList)

  My understanding of how to use this method is trapOid will refer to the OID of the Notification in my application's MIB and varBindList is any additional parameters to send. So, how/where does Alarm MIB fit into this?

Another requirement is "SNMP support must be comformable with Alarm Reporting Control MIB (RFC 3878)".

• What does this mean?
• What is Alarm Reporting Control MIB used for?
• Any relation to SNMP Trap/Notification?

Thanks.

Can anyone tell me how I can tweak the following top command so that it always runs in Solaris mode in a batch mode operation?

top -d 3 -n 2 -b -p <PID>

I need 'top' to output a process' CPU usage that had already been divided by the total number of CPUs, and as far as I know, that can be achieved with the 'I' toggle (Irix mode), but it only seems to be available in interactive operation (not in batch operation).

So I was wondering if this is indeed the case, or does anyone know any workaround for what I intended to achieve?

Thanks!

PS. OS: RedHat Enterprise Linux 5.

I need to get a memory usage in % from vmstat, but I don't quite understand some of the numbers relating to memory displayed in vmstat.

In particular, given an output like this

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 1  0 139728  45396 199128 1236360    1    2     4   622    3    1 51  4 43  2  0

What is the amount of total memory of the system? Is it 'swpd' + 'free' + 'buff' + 'cache', which total to 1620612?

What is the free amount of memory of the system? Is it 45396, as displayed in the 'free' column?

The problem is they don't add up or even look close to what 'top' reported. The output of 'top' which I took around the same time as 'vmstat's above is:

[...]
Mem:   4059616k total,  3965504k used,    94112k free,   200020k buffers
[...]

So...I am assuming there must be hidden numbers/options in 'vmstat' that I didn't know of?

I need to use 'vmstat' for this purpose and not other commands as this is what the requirement stated.

So ideally, what I want to achieve from 'vmstat' is the % memory usage, as in:

<used_memory>/<total_memory> * 100%.

Thanks!

These are pretty much questions from a newbie. (I have looked at the other related questions and answers, but none seemed to be exactly answering my own original questions.)

I need to remotely retrieve, parse, and report in a Java program the CPU and memory usage of a Linux machine. These should be done in two separate commands instead of one to decouple them to make it easier if one command needs to be changed in the future.

So my questions are:

• What is the best command to use to retrieve the total CPU usage of a machine for this purpose?
• What is the best command to use to retrieve the total memory usage of a machine for this purpose?

By best, I mean the output of the commands are:

• Standard (independent/should be the same across the Linux flavours -- not mandatory, but would be good. target OS though is RHEL 5)
• Can easily be parsed (not cluttered with other information I am not interested in).

Thanks!