[H-GEN] partitioning again

[James McPherson]

(Note reply-to: being general at humbug.org.au vs James McPherson <jmcphers at laurel.ocs.mq.edu.au>)


Robert Brockway writes:
 > On Tue, 11 May 1999, David Jericho wrote:
 > > > Yep, ok, 1 partition per OS, but other than that, my original question
 > > > still stands - do we need to bother with partitioning anymore, or is it
 > > > now a false idol :)
 > > For servers and the like, I'm still fairly religious with respect to 
 > > paritioning. The last thing we want is someone DoS'ing the filesystem
 > > and stopping a root login.
 > So far I've been religios about it too :)  But if ide really is
 > dynamically allocating stuff all over the disk then we are kidding ourselves :)

has anybody got any hard facts on the IDE interface? I find it hard to believe 
that an IDE will write data damn near anywhere it wants, especially since
(afaict) it does make use of the partition table to tell it what its
internal boundaries are. 

 > > For a home PC, I gave up a while ago with the 7 partition thing for unix. 
 > > I just got sick and tired of having to shuffle data around when I ran out of
 > > space when all I wanted to do is try something out. Maybe a seperate
 > > partition for /home, but everything else is on the one.
 > 
 > blake has 8 partitions but all other boxen have 1 each :)

well from an enterprise point of view (ie we run oracle ;>), that sort of
scheme is laughable because there are just too many things which can go wrong
if there is not enough space - we can't afford that possibility. On the
machine I admin, we generally have two internal disks (we only do scsi btw),
and any number of external disks on separate fast/wide controllers on which we
have the following:


/dev/dsk/c0t0d0s0      57143   19234   32195    38%    /
/dev/dsk/c0t0d0s1     962582  399296  505532    45%    /usr
/dev/dsk/c0t0d0s4     448143  207353  195976    52%    /var
swap                 1069220  252500  816720    24%    /tmp
/dev/dsk/c0t1d0s0     480919  126977  329897    28%    /opt
/dev/dsk/c0t1d0s1     962582  476992  437461    53%    /home

^^these are the internal disks - luns 0 and 1 on the internal chain. 


/dev/md/dsk/d0       /d00
/dev/md/dsk/d1       /d01
/dev/md/dsk/d2       /d02

^^ metadisks (2x2.0Gb mirrored) for the immediate day to day application data
which are on two separate controllers

/dev/dsk/c4t1d0s0    /d06
/dev/dsk/c4t2d0s0    /d07
/dev/dsk/c4t3d0s0    /d08
/dev/dsk/c4t4d0s0    /d09
/dev/dsk/c4t5d0s0    /d10
/dev/dsk/c4t6d0s0    /d11
/dev/dsk/c5t0d0s0    /d03
/dev/dsk/c5t1d0s0    /d04
/dev/dsk/c5t2d0s0    /usr/local
/dev/dsk/c5t3d0s0    /d13
/dev/dsk/c5t4d0s0    /d12
/dev/dsk/c6t3d0s0    /d15
/dev/dsk/c6t4d0s0    /d16
/dev/dsk/c6t5d0s0    /d17
/dev/dsk/c6t11d0s0   /d18                 

these others are all 4.3Gb disks, some in "unipacks" and others (not enough
unfortunately) in "multipacks". Unipacks are single f/w disks in their own
enclosures, whereas multipacks hold either 6 or 12 f/w disks which each have
the SCA 80pin connector and the slot you slide them into determines which lun
they have.

Anyway, as you can see above, I probably allocate too much space to /usr and
maybe 50Mb less than I should have for /var - logfiles on these boxen make
the size of /var an important consideration. However, downtime is not
something that's easy to arrange (ie, weekends and urgent maintenance only) so 
I'm not going to bother resizing those partitions. 

While we're at it, what do people think about Solaris' use of tmpfs for
virtual memory? This what we're seeing at the moment on this particular
machine:

# swap -l
swapfile             dev  swaplo blocks   free
/dev/dsk/c0t0d0s3   32,3       8 1024472 721296
/dev/dsk/c0t1d0s3   32,11      8 1080712 770976   

interestingly, before we cut over to 100Mbit (hme0 is the standard 100Mbit
device - the hme stands for "happy meal" ;>), we were seeing about 50% swap
utilization - now it rarely gets above 30%. (Yes, that was the _only_ thing we 
changed).


Comments/queries anybody? Or is Solaris the Dark Side ? ;)


cheers,
James C. McPherson
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Unix Systems Administrator            Phone: +61.2.9850.9418
Office of Computing Services            Fax: +61.2.9850.7433
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