Multiple partitions on 1 and 2 Unix PC hard disks.
Augustine Cano
afc at shibaya.lonestar.org
Fri Nov 16 14:38:01 AEST 1990
In preparation for a 2 stage upgrade, I now seek some net advice.
The first stage of the upgrade is to install the large HD I just bought
(A priam 519, 1224 tracks, 15 heads, 190 Mb unformatted.) I would do
everything at the same time, but John's HD2 board is not shipping yet.
I already have a WD2010 and the P.51 option installed.
My original plan is to make 2 partitions of equal size in this new disk:
/ and /u. The pros and cons, as I see them are:
Pros: 1 - /u sees most of the disk activity, but being a separate
partition, will not mess up /. Since it can be dismounted, it
can be unfragmented easily with packdisk.
2 - / and /u will be large enough that they won't fill up immediately.
Cons: 1 - /usr/spool, which sees lots of disk activity, will temporarily
be messing up the / partition.
2 - activity in /tmp will also somehow fragment the root partition.
3 - having / and /u on the same disk would make for lots of head
movement. However, would this be any worse than the standard,
one-partition per drive, unix pc way of doing things?
4 - /usr/lib/news, with all its updating of log files, history
files and active file would fragment the root partition some.
I suspect, though, that giving /usr/lib/news its own partition
wouldn't be a good idea.
Later, when I get the HD2 board, I'll add the current drive (an ST-4096)
as drive 2. This drive will also be partitioned in 2 equal chunks,
roughly 40 Mb each. One will be /usr/spool and the other will remain
as a mostly empty space for backups, archives, or semi-permanent temporary
storage.
Another possibility is to have /tmp as the other partition on
the second drive. This would speed things up, but somehow I feel that a
40 Mb /tmp is excessive. How big should /tmp be, if it gets its own
partition? I have stuffed some pretty big things in /tmp before and it was
nice to have all the free space on the drive available, so maybe the speed
penalty of having /tmp in the / partition is worth it. Comments?
Also, I seem to recall that without re-linking the kernel, you
can only have 2 partitions per drive (in addition to /dev/fp000 and
/dev/fp001), is this correct? Does this also apply to the second drive,
without a swap partition? Also, would it do any good to have a swap
partition larger than 5000 blocks? (I also plan to add 1.5 Mb RAM to a
RAM-less combo board.)
At this point the pros and cons, as I see them now are:
Pros: 1 - /usr/spool will now have its own partition on the slower drive,
thus no longer fragmenting /.
2 - there will be plenty of space (~75 Mb) in / for /usr/man,
/usr/doc, /usr/src/, /usr/lbin, /usr/local and all the other
standard directories that don't change very often.
3 - if the 2nd drive quits, I can just dismount it, re-make
/usr/spool in the root partition and I'm in business again.
This is partially why I'd rather keep /u on the main drive
(size and speed (22 vs 28 ms) are the main reasons).
If the big drive quits, I'm in trouble :-)
Cons: 1 - like 2, 3 and 4 above, depending on where /tmp is put.
But is there really a disadvantage to having 2 drives and lots
of space? :-)
Opinions anyone? Those of you who have 2 HDs and/or multiple partitions,
how did you do it? Any other considerations I have overlooked? Have any
benchmarks been run on different partitioning schemes and what directories
were placed where? Will some programs be broken by the multiple partitions?
Which ones?
I'll post a summary of e-mail responses. However, posting might be
appropriate, since at least the participants in the big HD group buy would
benefit.
Thanks.
--
Augustine Cano INTERNET: afc at shibaya.lonestar.org
UUCP: ...!{ernest,egsner}!shibaya!afc
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