[rrd-users] Architecture independence for rrd files
j.halifax2 at seznam.cz
j.halifax2 at seznam.cz
Mon Jan 21 03:21:00 CET 2013
>It might be better to create a program to convert RRD files in one go
> (we can already do an XML export/import of course) though this too
>could be more trouble than it is worth.
I believe so, too. Reads/writes are done usually tens of thousands in
a monitoring period (with load peaks) while changing the architecture
of the machine is done once a several years...
In addition I believe that everyone who needed to export & import the
rrd files has written such a tool himself.
---------- Původní zpráva ----------
Od: Steve Shipway <s.shipway at auckland.ac.nz>
Datum: 21. 1. 2013
Předmět: Re: [rrd-users] Architecture independence for rrd files
"> I thought it would be a good idea on finding out how to make the rrd
> structure architecture independent, and if it's supposed to be, find
> out what's going on.
I believe Tobi is planning architecture-independence for the RRD file for
Making it arch-independent is not so easy (else it would have been done long
ago as this has been on the cards some time). There are several problems
relating to the generated C struct which is written to the file as created
1. endian - is it MSB first or LSB first (or middle byte first as in
2. 23/64 bit - how big is an integer? This adjusts the size of the struct
3. alignment - does your architecture demand integers be byte-aligned and
therefore generate padding bytes?
4. compiler peculiarities - some just do it differently at compile time.
The first is actively checked for by RRDTool (looking for different magic
numbers in the header) and - I think - so is the second. Although it knows
about them, though, working around it without losing a lot of efficiency
would be a big problem.
It might be better to create a program to convert RRD files in one go (we
can already do an XML export/import of course) though this too could be more
trouble than it is worth.
I think there is more discussion on this in the Github area Tobi has set up
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