Re: [9fans] off-wall idea, file server and SAN

Re: [9fans] off-wall idea, file server and SAN

[geoff]

what's the hardware you can't locate?  it's never been a problem
to obtain the buslogic bt-948 or 958 (now called the mylex multimaster
series).  scsi disks are readily available.  if you have the money,
hp scsi mmc optical jukeboxes (now in 9gb disk size!) are easily
found.  any old vga card will do, since the file server kernel
just runs in cga mode.  the intel 8255[789] ethernet cards
(ether express pro/100+ or something like that) can be found on any
street corner or intel's web site.

or is the problem cost?  there are cheaper ncr/symbios/whatever-they're-
called-this-week scsi controllers; it looks like the current driver
supports virtually all of them.  the 3com etherlink iii cards work,
but i think they're usually more expensive than the intel ee cards.
there's support for the dec/intel 2114x (`tulip') cards, but i
haven't tried them myself.

it's really not hard to assemble a file server and it's well
worth it.  u9fs and kfs don't really show off the system;
kfs at least is quite a bit slower (order of magnitude for
some large copies i did recently).  talking to a foreign file
server running ext2 or ntfs via nfs or smb prevents use of
some of the more interesting file modes (exclusive-access or
append-only) and ought to be slower.

as for ntfs being a unicode file system, note that it's unicode,
not utf; they seem to have dropped the ball on that.  from what
little investigation i did, it also appears to be just a checklist
item; i don't think many nt applications use unicode file names,
so the relevant code probably hasn't been exercised much.

Re: [9fans] off-wall idea, file server and SAN

[nigel]

> as for ntfs being a unicode file system, note that it's unicode,
> not utf; they seem to have dropped the ball on that.  from what
> little investigation i did, it also appears to be just a checklist
> item; i don't think many nt applications use unicode file names,
> so the relevant code probably hasn't been exercised much.

Furthermore, it's "case preserving but case ignoring", which is about 
as much use as a chocolate teapot, especially in the Unicode 
context.

Re: [9fans] off-wall idea, file server and SAN

[cnielsen]

On Mon, 5 Mar 2001 geoff@x.bell-labs.com wrote:

> what's the hardware you can't locate?
> it's never been a problem to obtain the
> buslogic bt-948 or 958 (now called the
> mylex multimaster series).  scsi disks
> are readily available.  if you have the
> money, hp scsi mmc optical jukeboxes (now
> in 9gb disk size!) are easily found.
> any old vga card will do, since the file
> server kernel just runs in cga mode.
> the intel 8255[789] ethernet cards (ether
> express pro/100+ or something like that)
> can be found on any street corner or
> intel's web site.

As proof that this is definitely possible, I
have a fileserver that I recently built with
modern components. The MB is a Tyan S1837
with onboard SCSI (symbios SYM53C896), fast
ethernet (intel 82559), and usable onboard
video.  I bought an HP MO jukebox (200fx)
from ebay for $1000 and built the server for
~$2500, which includes the pair of 72G SCSI
drives. For $3500 I have an awesome setup.

On the topic of SANs, I think it might be
interesting to introduce support for this
technology into plan9. Anyone else have
thoughts on this?

--
Christopher Nielsen
cnielsen@pobox.com

Re: [9fans] off-wall idea, file server and SAN

[peter huang]

thanks for the reply.  However, there was a point missing from my posting.
The purpose of file server is to serve files, while plan9 file system is
better than other file systems in many regards but it can only serve system
running plan9.  While this may not be a problem for most users in plan9 fans
but  if I built a good nice file system, I want the other machines on the
network able to use it, that include mswindows system, linux system, BE ....
I can't spend $3500 just to show I have the coolest file system on earth.  I
know there is an IDE version of the file server in work and that may suit my
need (low cost).  However, the bigger question remain, how do I reduce
redunancy and have one file server doing the right job in a hetergenous
environment.   It is possible to write a ifs (install file system) on NT,
but without implement 9p, I don't think it is useful, the same goes for
linux ext2.  The idea of SAN in my mind is quite similar to plan9 file
server but more target for a hetegrenous environment.   It would be cool to
take some SAN hardware, port plan9 file server on it, add support for smb
protocol and dvd-ram drive and become the one and only one file server on
the network.    It could be the file system for my Tivo box ;-)

Anyway, I like to see plan9 network as the backbone of a small network (such
as home network), machines boot from it or store files on it and never worry
about backup disaster or obsolete hardware (which was the vision).

regards
peter huang

Re: [9fans] off-wall idea, file server and SAN

[anothy]

i'm not entirely sure i understand your question, but here's a pass
at a reply anyway. if i'm off the mark entirely, just ignore me.

a "proper" plan 9 network consists of a seperate file server and cpu
server (maybe more, and probably some terminals). the file server is
designed to do one thing: serve the cpu servers (and terminals)
their file systems. any additional services, like dhcp/bootp and
tftp, also useful for booting, are provided by cpu servers. in that
spirit, i'd expect the "Plan 9 answer" to your question to be that
you'd implement whatever other file services you're looking for on
the cpu servers. you'd then run that service on the cpu server (most
likely in /bin/cpurc), and have clients look to that cpu server for
their service.

as an example, Plan 9 ships with a NFS server (and associated
utilities) that allow you to point Unix boxes (or pc's with NFS
clients) at a Plan 9 cpu server for file service. i've run
heterogeneous network with Plan 9 as the core and various different
Unix flavors talking to it (making backups, typically the worst part
of any Unix admin's job, a non-issue). it worked well, but not
perfectly (see below). but if you're looking for a protocol that's
not already there, the nfs server may be a good place to start.

i have a vauge recolection of someone working on an SMB server, but
i've never had a need for it and don't really remember if it ever saw
the light of day. anyone? other protocols, like Appletalk or whatever
you need, could be written in the same way: as user-level code for a
plan 9 cpu server. much easier than builing it into the file server.

note that there are flaws to the approach: you have to translate the
requests from NFS (or whatever) into 9p, which takes some time. for
casual use, it's not such a big deal, but it gets notably slow with
heavy load. also, the authentication schemes don't match, which can be
awkward. the Plan 9 nfs server provides a special hack for doing
netkey authentication, but it's definatly a hack. the hack can be
automated into the login process or something, but it's still ugly. but
it does work. and i think the general feeling (and certainly mine) is
that these flaws are well worth it to avoid including various protocols
(and thus additional complexity and posability for bugs) into the file
server, the part of the network where stability is most key.

note also that i know nothing about the "new" file server being
developed - it may make all these points false or obsolete, i don't
know. this is based on the current file server. the new 9p may also
address some of the authentication issues. again, i don't know.
-α.

[9fans] off-wall idea, file server and SAN

[peter huang]

Hi,

   as I struggle to find the correct hardware to install a file server, I
was wondering whether any has consider implement the file server using the
SAN (storage area network) technology.  It seems to be a good fit and the
component is more readily available than the current file server hardware
requirements.  Another one is allow foreign box/file system to be used such
as NTFS (!heavan forbid, but it is a unicode file system) or extended Linus
ext2 (ext2 with utf support).  I know u9fs exist but it didn't seems to
support all the functionality needed by a plan9 file system.   I'm
interested in any ideas on the feasibility on the subject.

thanks
peter huang