[comp.sys.apollo] Disk partitioning

gyp@maadfa.ma.adfa.oz.au (Patrick Tang Guan Yaw) (08/20/90)

The first thing I notice when I started work here is that none
of the disks here are partitioned, ie only a 

	/

rather than

	/, /usr, /usr/local, and so on.....

and so on.  I have been given the impression that the formal is
the norm as far as apollo is concerned.  Am I right? Is there a 
reason NOT to do so?   For all system administrators out there, 
how many of you actually partition your disk and what is/are
your main reason(s) for partitioning your disk.

Thanks in advance.
-------
Patrick Tang Guan Yaw,		Phone	 :	+61 6 268 8882
Dept. of Mathematics,	EMAIL-ARPA/CSNET :	gyp@maadfa.ma.adfa.oz.au
ADFA, Canberra, 2600.		UUCP	 :	..!uunet!munnari!maadfa.ma.adfa.oz!gyp
AUSTRALIA			ACSnet   :	gyp@ccadfa.cc.adfa.oz

thompson@PAN.SSEC.HONEYWELL.COM (John Thompson) (08/21/90)

> <<forwarded message>>
> 
> The first thing I notice when I started work here is that none
> of the disks here are partitioned, ie only a 
> 
> 	/
> 
> rather than
> 
> 	/, /usr, /usr/local, and so on.....
> 
> and so on.  I have been given the impression that the formal [sic] is
> the norm as far as apollo is concerned.  Am I right? 
I believe so.  I have certainly received no suggestions that I should
partition my disk into volumes.

> Is there a reason NOT to do so?   
Not partitioning your disks is (1) easier, and (2) lets you be sloppy 
(laid-back?) in administration.  I don't need to analyze the cpu
usage to try and find out how large my boot partition must be;  I don't
need to verify that the user-directories won't grow too large;  ....
The long and short of it is that I can take the unused disk space and make
it available to whatever needs it _at_ _the_ _current_ _moment_.  We have
a DN10020 that runs _MANY_ memory-hogging jobs simultaneously.  (It doesn't
actually need all the memory, but it allocates it 'just in case').  This
translates into disk usage for swap space.  Right now, it's using about
400MB of disk for virtual memory swapping!  Worst case I've seen is 
well over 1/2 a GB!  However, there are many times when we don't have that
much swap-space in use (for reasonably long periods).  During this time, 
that extra disk space can be used for local user storage, for temporary
scratch space, or anything else.  If the usage changes later on, I won't
need to re-partition the disk, either.  Also, it's more efficient (in my
opinion) to have a single large disk-space than several small ones.  Would
you rather have 50MB free in one spot or in 5 chunks of 10MB each?

> For all system administrators out there, 
> how many of you actually partition your disk and what is/are
> your main reason(s) for partitioning your disk.
We used to partition our 500MB FSDs at sr9.x.  We did this because the
SALVOL was/is very slow at sr9, and we didn't want a system crash to keep
the node down for an extended period.  At sr10, with it's faster SALVOL, 
we have gone to a single partition for each disk (and in fact, stripe
some disks to gain the extra 'big disks'.)

John Thompson (jt)
Honeywell, SSEC
Plymouth, MN  55441
thompson@pan.ssec.honeywell.com

As ever, my opinions do not necessarily agree with Honeywell's or reality's.
(Honeywell's do not necessarily agree with mine or reality's, either)

wilsonj@texas.UUCP (Jay Wilson) (08/21/90)

In article <1834@ccadfa.adfa.oz.au>, gyp@maadfa.ma.adfa.oz.au (Patrick Tang Guan Yaw) writes:
> 
> and so on.  I have been given the impression that the formal is
> the norm as far as apollo is concerned.  Am I right? Is there a 
> reason NOT to do so?   For all system administrators out there, 
> how many of you actually partition your disk and what is/are
> your main reason(s) for partitioning your disk.
> 

We use disk partitioning, to prevent nodes from crashing when they run  
out of disk space.  We currently have 25 file servers with the operating
system isolated from the rest of the disk.  I will mention that before
sr10.1, disk partitioning was VERY unreliable.  Also, if you wish to the
partitioned section of the disk automaticly mount/dismount at boot/shut,
use the BSD mount command.  The SYSV mount command does not always work.

collins@nvpna1.prl.philips.nl (Donal O Coileain) (08/21/90)

gyp@maadfa.ma.adfa.oz.au (Patrick Tang Guan Yaw) writes:
>For all system administrators out there, 
>how many of you actually partition your disk and what is/are
>your main reason(s) for partitioning your disk.

(I tried to mail this but the mail messages kept bouncing back......) 

We only consider it worth the effort on shared resources.
On our shared resources (file servers, DN10.000's etc) we give the OS it's
own logical volume (partition). The rest of the disk(s) is(are) allocated to
user data. The advantage of allocating a seperate logical volume to the OS
is users can't screw up the system simply by creating large data files, the
disadvantage is that you have to work for yourself how large the OS logical
volume should be, taking into account the size of the OS you plan to
install, the swap and process space needed (etc).