Philipp Niemann wrote:
> Hi,
>
> On Wed, 18.11.2009-20:06:44 +0200, Tom Feiner wrote:
>> That now we have diskstat_ [1] under the linux plugins in munin 1.4 alpha,
>> should we move the older iostat plugin to manual so they won't both be
>> autoconfigured?
>>
>> As far as I can see they both provide the same data, only diskstat_ is much
>> more detailed and useful.
>>
>> Any objections to moving iostat to manual?
>
> I wouldn't call my thought an objection. I think the diskstat_ plugin
> is very good to have a detailed look at the io on a single device. OTH I
> have some servers with lots of devices, that is about 15-20 disk
> devices. This will do a very long part of diststat_ plugin graphs which
> will take lots of cpu to be generated and lots of scrolling to find the
> right graph for a disk I am looking for.
>
> So I use the iostat and iostat_ios plugins to have a single graph for
> all devices (that updates automatically for new devices) and use
> diskstat_ only for those instances I wish to have a closer look at.
>
> So I would prefer to have iostat and/or iostat_ios in the standard
> plugin base. To me, diskstat_ is the plugin I set up manually.
>
> I still find the diskstat_ plugin of great value!
>
Hm... you raise a good point, diskstat_ does require a lot of scrolling on a
machine with multiple disks - and currently doesn't provide a summary graph of
all disks like iostat does.
The question is - what's the more likely scenario - a machine with 1-2 disks,
or a machine with multiple disks.
Another plus that iostat has is the autodetection of disks. diskstat_ needs
munin-node-configure to run to recognise a new disk.
Here's an example of a very large munin installation of debian dervers:
http://munin.debian.org/debian.org/comparison-week.html#Disk (username:
dsa-guest, no password). For installations such as this, the diskstat_ plugin
will indeed create a lot of graphs (3 for each disk), and having iostat from
in autoconf mode does show the (basic data) of all disks in one graph.
On the other hand, when there are i/o problems that need investigating, having
the diskstat_ plugin show the detailed info for each disk would be very valuable.
I guess the ideal solution for this situation would be to show only iostat in
the main page for each host, and once the user clicks on it, allow a drill
down into the more fine grained diskstsat_ info. Maybe this should be a
feature request for the next munin release after 1.4?
Tom
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