Date: Wed, 25 Jul 2001 13:08:50 +0200 (CEST) From: Alexander Leidinger <Alexander@Leidinger.net> To: gabriel_ambuehl@buz.ch Cc: paul@akita.co.uk, enriko.groen@netivity.nl, tony@saignon.net, freebsd-isp@FreeBSD.ORG Subject: Re: Redundant setup on a budget?? Message-ID: <200107251108.f6PB8pu10158@Magelan.Leidinger.net> In-Reply-To: <1241681557.20010725114735@buz.ch>
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On 25 Jul, Gabriel Ambuehl wrote:
> If that is not enough, we're currently implementing a monitoring
> system with many of the functionality found in netsaint (which
> unfortunately is crashing all the time on our machines and also a bit
> slow, OTOH, I can't yet say whether ours will be much faster) and
> NAT modifying features[1]. It isn't yet decided under what kind of
> license this
> thing will get released, but if someone's willing to play alpha
> tester, I could provide you surely with a free license so you could
> play with it. I also have an alpha version of a whitepaper
> on my disk but that one's in German (high class one, riddled with
> English fail over vocabulary), so I suspect it wouldn't help you
> very much.
But it's perhaps interesting for other people. Can you put it somewhwere
to download?
> Basically, the load balancing part is easy enough (look ipfilter and
> natd, both do it). Harder but still doable with a reasonable amount
> of work is fail over (l4check might be good enough for your uses, for
> us it was too limited). What's really hard is to mirror the servers
> in near realtime (and here are WE searching for a solution). While
> databases
> bring their own replication features, filesystems do not (with the
> possible exception of coda but that beast did neither work on my
> systems nor does it look like it's being maintained).
[...]
> What definitely doesn't work on most
> webservers (not on shared ones, anyway), is offline replication like
> standard rsync or cpdup as those take about 1h to simply check and
> update the twin of a 5 GB server which is not what I consider to be
> realtime (basically, I could agree on using any solution that doesn't
> create more than a 10 to 15min lag, even on big mailservers with
> hundred of thousands of files and dirs).
Perhaps you want to implement it on your own too...
For ufs:
man 2 kqueue
If you decide to implement it (there are interfaces to other languages -
at least to python - in the ports), please make the program modular in a
fashion it would be usable as a realtime tripwire replacement (e.g. let
it call 3rd party apps with "path" and "type of change" as arguments...
I already thought about this a little bit, but unfortunally I didn't
have time to implement it myself, but you're perhaps interested in some
ideas I have).
Bye,
Alexander.
--
The computer revolution is over. The computers won.
http://www.Leidinger.net Alexander @ Leidinger.net
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