[rrd-developers] Update ex post?

Thorsten von Eicken tve at voneicken.com
Tue Aug 24 17:48:24 CEST 2010

On 8/24/2010 8:39 AM, Tobias Oetiker wrote:
> Hi Thorsten,
> Today Thorsten von Eicken wrote:
>>> So, what's the approach those tools are using (I've never looked at any
>>> of those [nor have I looked *for* any ;-)])?
>>> Cheers,
>>> Sebastian
>> The splicing could also be very useful for restoring data. E.g., if a
>> monitoring server dies we can quickly replace it with a new one, but
>> that doesn't have any data. So all the RRDs start out empty and record
>> new data coming in. When we get the data from the failed one restored,
>> we'd like to splice the old and new together.
> another option (without modifying the actual rrd files) would be to
> asemble them while graphing based on information about which host
> was providing the service for what time span ... using a CDEF to
> turn all data outside the active periode to Unknown.
Yes, that's a good point. The problem I'm having is that some servers 
get upgraded on an approx monthly basis, that starts to get unwieldy 
when you're drawing the graph for the year. When I then generate an 
aggregate graph for, say www1 thru www10 it gets ugly (I'm actually 
generating aggregate graphs with up to 100 servers on them and I know my 
customers will be asking for even more).


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