29 Sep
2017
29 Sep
'17
9:19 p.m.
On Thu, Sep 28, 2017 at 6:20 PM, Larry McVoy <lm(a)mcvoy.com> wrote:
I dunno why all the hating on diskless. They actually
work, I used the
heck out of them. For kernel work, stacking one on top of the other,
the test machine being diskless, was a cheap way to get a setup.
Sure, disk was better and if your work load was write heavy then they
sucked (*), but for testing, for editing, that sort of thing, they were
fine.
We had a setup on Sun's running SunOS 4.1.x that I actually really
liked; I believe it was referred to as "dataless". The root
filesystem, /tmp and swap were local, along with scratch space on an
arbitrarily named filesystem (I think we mounted that on /scratch, but
I can't remember the details at this point). The difference between
/tmp and /scratch was that the latter persisted across reboots and we
backed it up. /usr, /usr/local came from a fileserver on the local
ethernet and /home was automounted. Users didn't have local root
access, and we kept / pretty well updated using rdist and some
home-grown scripts; basically, we could throw / away at any time on
any machine and rebuild it without losing much. Since all the
administrative data like passwd, group et al all came from NIS it was
almost the best of both worlds: the consistency and central management
of diskless machines and the performance of having local disk. When
the user wanted to do something temporary and IO intensive s/he just
did it in /scratch or /tmp; everything else lived on the file server.
We could deploy a new machine by netbooting it and dd'ing an image
onto the disk. A script ran the first time it booted up that made
whatever small modifications were necessary to files in /etc (this was
before jumpstart and officially sanctioned network install systems)
and away one went. It took about 10 minutes before the user could take
over and get to work.
It was a really nice, comfortable system. Of course, it wouldn't fly
in this day and age for security and other reasons but back in the
early 90s it was great. I didn't find a system I liked as much until I
met plan9. In many ways, the environments were on these days feel like
a regression.
- Dan C.