Changing hard disk partitions

Kevin L. McBride klm at gozer.UUCP
Wed May 1 05:22:15 AEST 1991


In article <1991Apr23.131919.8083 at virtech.uucp> cpcahil at virtech.uucp (Conor P. Cahill) writes:
>peter at ficc.ferranti.com (Peter da Silva) writes:
>
>>In article <1991Apr13.164855.1252 at virtech.uucp> cpcahil at virtech.uucp (Conor P. Cahill) writes:
>>> for a 140MB disk I would compine /root and /usr so that they share 
>>> tmp space.
>
>>And I'd suggest the opposite for any disk over 40 MB. Why combine them?
>
>By combining them you share the extra space that you need to allocate for 
>building kernels, /usr/spool, /usr/tmp, and /tmp.  Otherwise you have to 
>calculate what you think you will need and never be able to go over in either
>partition. 

Yes, but when you graduate to multiple and/or BIG disks, you might
want to do things similar to what I have done:

1)  First drive: Micropolis 318 MB ESDI

    Contains: / (root) (make it bigger than you KNOW you will ever need)
              swap     (ditto)
              /usr     (ditto)
              /extra (98 MB of *slack* that I can use anywhere, typically
                     for archiving/unarchiving source tapes, etc. Mounted
                     only when needed.)

    in that order.  Note that not only do I have separate root and /usr
    partitions, but I have swap physically located between them.  Tests
    have shown that this CAN be a big performance win in a heavily loaded
    system that is paging a lot.  It reduces head travel and hence, seek
    time, to the swap partition by placing it in the middle of the disk
    rather than at the end.  Note that ISC's installation scripts won't
    set up the disk this way.  You have to hack some to get there.  The
    most convenient way to do this is to have an extra disk that you can
    partition by hand AFTER you have installed the system.  Copy the file
    systems from the 1st disk onto the 2nd and then take your system apart
    and make the 2nd disk the 1st.

2)  Second drive: Seagate 1.2 GB SCSI

    Contains: /usr/spool (320 MB for Usenet, Mail, and freeware archives)
              /mit       (275 MB for X11R4 sources and development work)
              /usr2      (remainder of disk for user's directories)

Granted, not everyone is going to go to these extremes, but similar
things can and, in some circumstances, should be done even on systems
with disk space totalling less than 400MB.

In the other extreme, I was working at a site that had numerous ISC
boxes connected on a network to a DECSystem 5400 with multiple Gigs of
disk space.  The ISC boxes were setup essentially 'dataless'.  The
local disk was an 80MB Quantum which contained root (/) and swap.
/usr was part of the root partition.  All user's directories were
mounted from the file server, as was /usr/mail and /usr/spool/news.

The 80MB Quantum drive is just big enough to load all of the ISC
Architech Workstation Developers package and Motif and give you a
reasonable amount of swap space.

--
Kevin L. McBride     |Contract programming (on and offsite)   |Brewmeister and
President            |X, Motif, TCP/IP, UNIX, VAX/VMS,        |Bottle Washer
MSCG, Inc.           |Integration issues, Troubleshooting.    |McBeer Brewery
uunet!wang!gozer!klm |Reseller of ISC UNIX and Telebit Modems.|Nashua, NH



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