[BBLISA] RAM for cluster net boot?

[Daniel Feenberg]

On Wed, 6 Feb 2008, Daniel Hagerty wrote:

> Scott Ehrlich <scott at mit.edu> writes:
>
>> I'm looking at building a small cluster of disk-less 1 or 2U servers and will
>> probably use CentOS 5.
>
>    It's not 1990, so the immediate question is "what benefit is going
> diskless giving you?"

Its the convinience of having only one image to keep up to date, of being 
able to make universal changes with a single edit, of knowing that none of 
the systems was out of sync, the ability to swap OS with a single edit 
to /etc/dhcpd.conf etc. Of course, it is nice to have local swap 
and /tmp, the convinience comes from effective statelessness which a local 
disk used only for swap and /tmp does not vitiate.

I understand that cfengine is an alternative, but not always a superior 
alternative. In our case the amount of ethernet traffic from program 
loading is trivial compared to data I/O, so there is little benefit to 
us in keeping /usr local. Scott may be in a similar position.

Daniel Feenberg

>
>    Back in the day when diskless was popular, disks were insanely
> expensive, and several of the canonical diskless platforms
> (e.g. sun3/60s or whatever that particular pizzabox model # was) could
> actually do NFS writes faster than a local disk (provided the NFS
> server could keep up).
>
>    Neither of these properties are true anymore.
>
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