[rrd-developers] teting mmap/mtime updates

[Tobias Oetiker]

Hi Bernhard,

> >what I am doing now, is to add a utime call right after open for
> >all rw mmap access.
>
> Please don't do that for the general case. This penalizes everybody
> just because somebody may use broken kernels.
> If you think that doing a bypass in rrdtool for that kernel-bug (samba and
> alot of other packages also suffer from this, so only bypassing it in
> rrdtool is pretty useless) then please wrap it in some
> #if defined __linux__
> #include <linux/version.h>
> #if LINUX_VERSION_CODE < 0x020615
> /* kernels prior to e.g. 2.6.21 */
> # define __BROKEN_POSIX_MSYNC_MTIME
> #endif

I integrated the test (including the sync) into configure and am
enabeling the code only where necessary. So for all 'good'
implementations it will not be active.

> So people with broken kernels can have their mtime updated manually
> and the sane rest doesn't have to suffer.
> Let me note that this whole mtime-is-not-updated is really only
> a cosmetic issue for rrdtool. If you want to know if the rrd was
> updated, just use "last" or "lastupdate" or the like.

Well people do run backup on their rrd tool stores ...

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