[dundee] TuxRadar - The Great Boot Race

[Rick Moynihan]

2009/11/4 gordon dunlop <astrozubenel at googlemail.com>:
>
>
> 2009/11/3 Rick Moynihan <rick.moynihan at gmail.com>
>>
>> Good point, and well worth a more detailed look!
>>
>> Parallelising bits of the startup process seems like it's going to
>> bring more advantages when we're running those 100 core CPU's Gordon
>> mentioned.
>
>   Here is an article about the parallelization of the process:
>
>  http://www.h-online.com/open/features/Faster-booting-with-Upstart-848690.html
>
> Do you think Erlang could be used to speed up things more? :)

No, Erlang's not really suited to scripting (though there is escript
if you want to) and the kinds of issue that occur in managing O/S
processes.  This said upstart and its event based architecture share
some similarities with Erlang... and you could certainly write
something like upstart in Erlang, its just unlikely you'd want the
added dependencies and complexities of an Erlang VM, so soon in the
boot cycle, before you'd setup basic system services (such as mounting
filesystems, etc...)

Regarding parallelism Erlang is primarily about single process (at the
O/S level) concurrency and transparent distribution of
services/processes to other machines/nodes (scaling out)...  It's main
use is therefore in the heavy lifting, i.e. writing backend network
services, which need to handle lots of things at once (high
throughput) with zero downtime.  Hence why Erlang is used a lot for
things like Message Queues (e.g. RabbitMQ), Network Servers (e.g.
Ejabberd, egitd, Yaws), Distributed Data Stores (e.g. CouchDB, Amazon
SimpleDB, mnesia)... It's also got a proven track record in high
availability low level network and telco services (handling packets at
the bit/byte level) with the AXD301 being Ericssons flag ship product
built in Erlang and achieving a reported nine nines (i.e. 99.9999999%)
availability (though I think this figure is an over estimate.... with
5 nines being commonly cited from various sources).

The recent O'Reilly book is a must for anyone interested in Erlang and
is definitely the best book on Erlang currently available:

http://oreilly.com/catalog/9780596518189

R.