[rrd-users] building a huge rrd / any limitations?

Sebastian Harl sh at tokkee.org
Wed Jun 11 23:34:28 CEST 2008

Hi Karl,

(Not going to comment on the usefulness of having such large RRD's. ;-))

On Wed, Jun 11, 2008 at 03:14:18AM +0200, Karl Fischer wrote:
> I'm planning to create a really huge rrd with 5-10 million rows
> holding about 100-200 entries each, so the complete rrd will reach
> a size of 5 .. 20 GB ...
> Are there any problems to expect when creating and using an rrd
> that size? Any limits to hit (like 32bit file pointers or so)?

Yes, currently RRDtool is basically unaware of large files. Some 64 bits
architectures might happen to support that anyway but I don't think
that's guaranteed.

Attached to this E-mail you can find a patch that adds _very_ _basic_
large file support. Please note though, that this patch won't help you
much in your current situation as other parts of RRDtool still cannot
handle large files (see e.g. one of my replies to Debian bug #451852
[1]). However, that patch is the base which is necessary to further go
into that direction. See the patch description for further details.

For that patch to be effective, it is necessary, that all source files
that work with files directly include rrd_config.h (either directly or
by including rrd_tool.h) (which is currently the case). Also, fseek()
and ftell() should not be used but replaced with the newly added macros


[1] http://bugs.debian.org/451852#49

Sebastian "tokkee" Harl +++ GnuPG-ID: 0x8501C7FC +++ http://tokkee.org/

Those who would give up Essential Liberty to purchase a little Temporary
Safety, deserve neither Liberty nor Safety.         -- Benjamin Franklin

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