using sysinstall upgrade as a repair solution

[Kevin Kinsey]

Jerry McAllister wrote:
> 
> The long ago origins of making things in many partitions was when
> disks were much much smaller.  So were backup media.   It was common
> to have each piece on a separate disk.   Then disks got big enough
> to put more than one part on and so on.
> 
> Now, there are a couple of good reasons to still divide a disk in to
> partitions.  One is mentioned, sort of, above.  You want to isolate
> areas that may grow unexpectedly from critical disk space.  So, /var
> which contains logs and database stuff and spools gets its own partition
> to keep it from over-filling root.   /tmp and user home directory space
> are also such disk areas whose growth might not be predictable.
> 
> Another reason is for convenience with backups.   You may want to
> reduce the size of partitions that are being backed up, either to
> fit media or to be more convenient.  If only stuff in the partition
> with users' home directories changes, then you only have to make
> regular backups of that.  The other parts you only backup when you
> make a new install or whatever.  Some things like /tmp you don't bother
> to ever back up.    It also can be less to have to restore if one 
> partition goes belly up, though that is less true nowdays when the users' 
> space (not necessarily /usr - that is an old convention.  Now it is 
> common to use /home for users' home directories, since /usr really contains 
> installed software) may be by far the largest space on a system, depending 
> on how the system is used.  
> 
> Another reason to break things up is to have to load the least amount
> possible when there are problems.   You have to have / to boot in to
> single user mode to work on things.  But you don't have to have the
> rest of the stuff.   The smaller you make root the less likely some
> disk problem will show up in the root partition, making it more likely
> you can get at least some of the system up to work on the problem.
> 
> The fourth reason to have separate partitions is to make it easier
> to isolate things.   You may want to make a certain amount of space
> available for users to write in, but want to keep them out of other
> space.   There are various ways to do it.   Having things grouped
> conveniently in some defined area makes it a little easier.
> 

What Jerry said ;-).  Thanks for expressing what I couldn't OTTOMH.

>> Incidentally, 150MB doesn't seem very large for a root partition IMHO. 
>> I've not read the handbook recently, but I generally use a gig for /.
> 
> If you divide out /var and /usr and /tmp and /home, then 150 MB is
> plenty for root.   I am currently using about 120 MB on this machine
> which is due a good cleanup.  

I only partition /, /var/, and /usr/, so /tmp stays in the root slice; I 
make mention of this fact (150M being small) because of the 
previously-mentioned case in which installworld puked because / was full 
(this *was* with a separate /tmp) and there was nothing really there 
except default stuff (had been a DesktopBSD system, maybe someone with 
more experience there could comment).  The box was going from 5.3 under 
an (older) DesktopBSD test install to FBSD 6.2; I worked 'round the 
issue by moving /stand, but ended up re-installing 6.2 from CD to give a 
slightly more junior guy more experience with sysinstall (AAMOF I've 
made him do it on two boxen today, heh heh heh)....

Kevin Kinsey
-- 
Life is what happens to you while you're busy making other plans.
		-- John Lennon, Beautiful Boy