[rrd-users] NO ERROR returns trying to update the rrd file which no longer exits.

Tobias Oetiker tobi at oetiker.ch
Tue Oct 5 10:43:13 CEST 2010

Hi Yuya,

> On 10/05/10 09:59, Yuya wrote:
> > 4. Remove the rrd file from HOST A.
> > 5.Execute "rrdtool update --daemon" on HOST B to udpate the rrd file already removed from HOST A.
> > NO ERROR returned, which seemed strange since there no longer existed the rrd file what should be updated.
> >

Today Andreas Maus wrote:

> A file handles point to an inode not to a path, so I think rrdcached
> is still able to write data to the file handle.

as far as I underrstand the inner workings of rrdcached it only
access the file once it writes to it (aka flushes) this means that
it can not know if the file exist or not at update time. After all
the whole puropse of rrdcached is to minimize IO. Checking for
rrd validity at update time would negate that purpose.

if you work with rrdcached and modify the 'database' directly, I
would suggest to stop cached first and then restart it. Same
stories with all databases.

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

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