Re: Copy slower than rsync Re: Bugs and features

[Mark Burgess]

On  8 Nov, Adrian Phillips wrote:
>>>>>> "Mark" == Mark Burgess <mark@daneel.iu.hio.no> writes:
> 
>     Mark> I looked at this a while back and there are several issues
> 
>     Mark> * seem to be version differences with rsync and cfengine
> 
>     Mark> * cfengine spreads things out over time (low CPU, slower
>     Mark> total time) rsync (high CPU, short total time). Thus with
>     Mark> multiple connections one would expect cfengine to
>     Mark> survive/scale longer than rsync.
> 
> Well, even a 1+GB partition only takes a few seconds on a fast,
> lightly loaded server with rsync even using ssh. Obviously when there
> are lots of differences then rsync is going to chew memory.
> 
>     Mark> * rsync trusts everything and caches like mad to go fast.
> 
> This is rsync using ssh so there is a reasonably level of security
> involved, unlike rsyncs own server.


That is not the same thing. ssh == ecnryption. Encryption is not
the issue. Cfengine runs exactly as fast as ssh with copy.

 
>     Mark> * cfengine trusts very little and does lots of checks. (In
>     Mark> my opinion this is the correct approach, since speed is
>     Mark> rarely of the essence in system admin).
> 
> Its not just speed thats the question. Obviously a process
> (continously) running for 4 minutes is going to eat more resources
> than one running for 4 seconds no matter how heavy the latter is for
> its life.


Yes, but you are getting more for your money. Checks and security.
PLease do not associate security with encryption. Encryption is
obscurity.

> Anyway, currently I'm switching all my large copies over to
> shellcommand rsyncs to avoid this because I prefer to have cfagent
> running for as short a time as possible. Other people may have other
> preferences.

This seems irrational. It doesn't matter that its there hanging around
doing a good job rather than a quick job. If it takes a while, other
cfengines will do what else needs to be done transparently.

> And note, this "complaint" doesn't detract from cfengine's overall
> usefulness. I've never found anything that could easily replace it for
> small to large scale machine management.

I considered this seriously when the "complaint" was made and decided
that the two scenarios were not compatible. If you want fast and dirty,
go for rsync. If you want careful and secure, go for cfengine. You
cannot have both.

M