Disk Partition Percentage

[Robert Meyer]

Well, I started to answer this once and my laptop shut down.  I guess you have
to pay attention when it says that the battery is almost dead...

Anyway, if you want to get technical about it, the reason that swap space is
twice main memory is that in the old days, before fire, the system needed
someplace to put crash dumps in the event of a kernel crash.  It would copy out
all of main memory to swap space.  You could then use a crash dump analyzer to
poke through the smoking remains to find out what went wrong.  The system would
only actually use whatever was left after the amount needed for a crash dump
was  mapped out for swap.  This is why we'd make it twice the size of main
memory.

We also would normally place swap space between / and /usr file systems.  This
was to minimize the seek time necessary to get to the swapper when a process
needed to be swapped out (remember: before fire and demand paging?).  If the
swap was in the middle of the disk, then the average seek necessary to reach
the swap space was about 1/4 of the disk.  The maximum seek was 1/2 of the disk
travel.  I still do things that way (at least try to get swap in the middle),
even though most systems typically have more memory so they don't page as much.
 If you put the swap space at the end of the disk, the average seek to the swap
space is 1/2 of the disk and the maximum is the full travel of the heads.  You
can see where this could become a performance issue if you were running a
memory poor system.

And that's the way it was, circa 1984.

Cheers!

Bob
--- Cyber Source <peter at thecybersource.com> wrote:

> sorry, forgot the rest of the question. I would keep /boot to a 100MB 
> and / for the entire drive except for leaving 500MB for a swap partition 
> and put at the end of the drive, here is my fdisk -l.
> 
> Disk /dev/sda: 36.7 GB, 36703934464 bytes
> 255 heads, 63 sectors/track, 4462 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>  
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sda1   *           1          13      104391   83  Linux
> /dev/sda2              14        4396    35206447+  83  Linux
> /dev/sda3            4397        4461      522112+  82  Linux swap
> [root at Office peter]#
> 
> Any thoughts on the swap partition guys? I keep the swap always at 
> 500MB. The rule to double the RAM gets crazy when you have 512MB of RAM 
> and end up with a 1GB swap, this seems like such a waste. Am I wrong in 
> thinking that? Thoughts?......
> 
> Frank Kumro wrote:
> 
> >I am wanting to dump my current disk setup which consists of a swap
> >partition and a / partition. What other partitions would I need to
> >create? (i want home seperate and what else???). Also what percentages
> >should I use for disk space for each partition? I say percentages
> >because I have many machines which I would like to add these changes
> >too however they all vary in size. Thanks again guys!
> >
> >  
> >
> 



		
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