[rrd-users] rrdtool backed mrtg using massive amounts of memory

[Steven Hartland]

Hmm I may well have jumped the gun with the diagnosis there.
I've just seen it doing the same thing with mmap disabled.

I setup full debug and restarting the the thing that stands
out is the following:-

2009-05-13 15:54:58 -- --base: Check for Thresholds
2009-05-13 15:54:58 -- --base: Act on Router/Target as01.gswams_26
2009-05-13 15:54:59 -- --base: Get Current values: in:1524189419937, out:1124283784349, up:undef, name:undef, time:1242225809
2009-05-13 15:54:59 -- --base: Create Graphics
2009-05-13 15:54:59 -- --base: start RRDtool section
2009-05-13 15:54:59 -- --base: maxi:125000000, maxo:125000000
2009-05-13 15:54:59 -- --log: RRDs::tune(as01.gswams_26.rrd -a ds0:125000000 -a ds1:125000000 -d ds0:COUNTER -d ds1:COUNTER)
2009-05-13 15:54:59 -- --prof: RRDs::tune as01.gswams_26.rrd - 0.091s
2009-05-13 15:54:59 -- --log: RRDs::update(as01.gswams_26.rrd, '1242225809:1524189419937:1124283784349')
2009-05-13 15:59:50 -- --prof: RRDs::update as01.gswams_26.rrd - 290.345s
2009-05-13 15:59:50 -- --log:  got: ???/???

So 290 seconds to do an single row update when this is the only
thing the machine is doing?

What could possibly be causing this?

    Regards
    Steve

----- Original Message ----- 
From: "Steven Hartland" <killing at multiplay.co.uk>
To: <rrd-users at lists.oetiker.ch>
Sent: Wednesday, May 13, 2009 2:13 AM
Subject: [rrd-users] rrdtool backed mrtg using massive amounts of memory


> Having an issue here where mrtg which rrdtool backed in our
> case is using a massive amount memory 5GB+ after a short
> period of time.
>
> The config isn't that big just 371 targets. I seem to remember
> a thread a while back suspecting mmap causing an issue so
> I disabled it on the off chance this would help and sure
> enough the mrtg perl process is now ~500MB.
>
> So why would mmap option cause such massive memory usage?
>
> rrdtool version: 1.3.7
> mrtg version: 2.16.2,1
> FreeBSD version: 7.0-RELEASE AMD64
>
> Its not just memory though actual processing speeds are
> massively effected. The machine this runs on does two things
> mrtg network port starts and server stats read from mysql DB
> tables.
>
> With mmap enabled the a run of the server stats was taking
> over 15mins without it ~1 1/2mins, so a massive difference.
>
> The machine has only got 4GB of ram so I expect the memory
> usage is seriously dragging down the speed but obviously
> the end result is a major slow down when enabling an option
> which should be increasing performance.
>
> Comments, thoughts etc?
>
>    Regards
>    Steve
>
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