[collectd] swap plugin improvements

[matthew sporleder]

On Wed, May 19, 2010 at 5:42 AM, Florian Forster <octo at verplant.org> wrote:
> Hi Aurélien,
>
> thank you very much for your patches :)
>
> On Tue, May 04, 2010 at 03:05:11PM +0200, collectd at wattapower.net wrote:
>> The second patch adds support for the two-args version of swapctl() in
>> the actual swap plugin code.
>
> I've applied the first two patches to the master branch, so they will be
> included in the next feature release of collectd.
>
>> As a consequence the returned metrics are quite different. "reserved"
>> is no more, and "used" + "free" reflects the total amount of on-disk
>> swap space. This is in contrast to the libkstat implementation where
>> "used" + "free" + "reserved" added up to more than on-disk swap, as it
>> comprised a variable amount of RAM.
>>
>> In my opinion the previous metrics have their interest and should be
>> preserved. But as they reflect the behavior of the Solaris virtual
>> memory subsystem rather than strictly speaking swap devices, maybe
>> they should be moved to another plugin like vmem ?
>
> I don't know enough about the memory management of Solaris to have an
> opinion here, maybe someone with more knowledge can share his opinion?
>
> In general, now would be the perfect time for such a change since the
> next release may include backwards incompatible changes, such as this
> one. I've added a note to the “Plans for 5.0” wiki page [0], so I don't
> forget to check up on this patch before releaseing 5.0.
>
> Regards,
> —octo
>
> [0] <http://collectd.org/wiki/index.php/Plans_for_5.0>
> --
> Florian octo Forster

I would say you want to get numbers that match swap -l.  (the last two
numbers are blocks allocated and blocks free of just swap.)