[rrd-developers] two problem about RRD UPDATE

[Tobias Oetiker]

Today Florian Forster wrote:

> Hi Lily,
>
> On Sun, Mar 15, 2009 at 10:39:37AM +0800, lily wrote:
> > How can I keep the data in memory? Use the mmap ? Is upgrade the
> > version to 1.3.6 wil be OK  or I have to something in my code ?
>
> basically, all you have to do is have more memory - the operating system
> should do the rest..
>
> > My rrdtool is the 1.2.27, I don't know if I upgrade my version to
> > 1.3.6, Is there some *compatibility *problem ?
>
> Version 1.3 introduces a changed file format. It can still work with RRD
> files created by version 1.2, but not the other way around.

Note this changed format is only active when you create a
particular type of holt-winters RRAs. In general the same format
as in 1.2 gets created.

> > > > You did mount with `noatime' and `nodiratime', right? While this doesn't
> > > > perform miracles, it'll certainly increase performance some percent..
> >
> > Yes , I did not do that . But if I do that , I don't have the access
> > time , rigth ?
>
> Uhm, yes.. That's why it's called `NOatime'.. What do you need the
> `atime' for? Are you sure you don't confuse this with the `mtime'?
>
> I've heard of a system which relied on `atime' to clean up dynamically
> created files (they were using the file system as some kind of cache,
> really). When IO killed that system, they started deleting files a fixed
> time after they were created (possibly recreating busy items/files),
> which improved performance A LOT.
>
> > Now I reduce the number of the file from 12K to 8K , I have not
> > encountered the problem yet. So I think the reason is the high load .
>
> I guess that your 12k files just do not fit into your 4 GBytes of RAM
> and those 8k files to. I'd interpret this observation as indication that
> more RAM is the easiest way out of your performance problems.
>
> Regards,
> -octo

cheers
tobi

>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900