Re: Issues with Cacti running very long rrdtool commands

This is IMHO a restriction of the underlying OS. At least it is known, that some
of those have a restriction like that
Reinhard

Am 23.10.2014 um 07:51 schrieb Ryan Garland:
> To follow up on this, I did some tests with the graph that is failing vs
> the graph that is working by adding:
> 
> print strlen($command_line);
> 
> inside the following function in rrd.php:
> 
> function rrdtool_execute
> 
> The graph that fails has a string length of 131104, the graph that succeeds
> has a string length of 130864.  So, it would seem as though we are running
> into a 131072 limitation.
> 
> Any ideas how we can get around this, or get Cacti to run the command as if
> it were at the command prompt which does not seem to have such a limitation?
> 
> Cheers,
> 
> Ryan
> 
> On Wed, Oct 22, 2014 at 9:47 PM, Ryan Garland <[email protected]> wrote:
> 
>> I believe I am running into a character limit for the commands that
>> rrdtool can successfully run.
>>
>> I currently have a stacked aggregate graph with 1376 line items (3/4 of
>> which are the Legend lines).  This graph renders just fine, and with Debug
>> mode turned on, after the long rrdtool command, rrdtool returns "OK".  The
>> character count of the command (including any white space) of this command
>> is 132961.  (Yes, I know that's a lot - I have my reasons :))
>>
>> However, as soon as I add a new line item to the graph, the graph no
>> longer renders, and with Debug mode turned on, rrdtool does not return OK
>> -- it merely shows nothing.  The character count of this command is 133204.
>>
>> Here's the kicker:  When the failing rrdtool command is manually ran at
>> the system's command prompt, the command succeeds.  It seems that only
>> within Cacti does the rrdtool command not work.
>>
>> I have done a lot of research and found some seemingly related information
>> ( such as http://www.mail-archive.com/[email protected]/msg05522.html )
>> which discusses command length limitations by the OS / kernel, limiting to
>> 131072 MAX_ARG_STRLEN, but:
>>
>> 1) this number is slightly lower than the length of the full rrdtool
>> command that is succeed, and
>> 2) if that was the problem, the command should not succeed when manually
>> run at the command prompt
>>
>> So what is Cacti doing when it runs rrdtool that could be limiting the
>> command length?  Does anyone have any suggestions as to how to resolve this
>> apparent limitation?
>>
>> Any help is appreciated.  Software versions listed below.
>>
>> Cacti Version 0.8.8a
>> PHP Version 5.3.10-1ubuntu3.14
>> Ubuntu Version 12.04
>> RRDTool Version 1.4.x
>>
>> Ryan
>>
> ------------------------------------------------------------------------------
> _______________________________________________
> cacti-user mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/cacti-user
> 

------------------------------------------------------------------------------