[clug] partition tables in memory

[Andrew Pollock]

On Sat, Apr 16, 2005 at 05:02:42PM +1000, Kim Holburn wrote:
> Just to make this clear,
> 
> The normal method of making swap is AFAIK :
> 1) make a partition,
> 2) run say:
>    mkswap /dev/sda8
> 3) then:
>   swapon /dev/sda8.
> 
> But in this case the kernel cannot see the partition:
> # l /dev/sda[78]
> brw-rw----    1 root     disk       8,   7 Mar 15  2002 /dev/sda7
> brw-rw----    1 root     disk       8,   8 Mar 15  2002 /dev/sda8
> # cat /proc/partitions
> major minor  #blocks  name     rio rmerge rsect ruse wio wmerge wsect 
> wuse running use aveq
> 
>    8     0   35545728 sda 688792 1156813 14762148 7980560 13470841 
> 37027503 404260530 43342130 1 7507370 51338980
>    8     1     979933 sda1 112258 395055 4058776 542960 59256 312356 
> 3012928 1375120 0 443990 1923240
>    8     2          1 sda2 0 0 0 0 0 0 0 0 0 0 0
>    8     5    4883728 sda5 382733 622455 8041500 6313750 10902982 
> 16989694 223279552 30965690 1 5792500 37274880
>    8     6    2931831 sda6 154552 52632 1657500 360210 843641 4091059 
> 39488440 2485030 0 946790 2845000
>    8     7     979933 sda7 39198 86298 1003524 763420 1664957 15634399 
> 138479640 8516260 0 543100 9294370
> # fdisk -l /dev/sda
> 
> Disk /dev/sda: 255 heads, 63 sectors, 4425 cylinders
> Units = cylinders of 16065 * 512 bytes
> 
>    Device Boot    Start       End    Blocks   Id  System
> /dev/sda1             1       122    979933+  82  Linux swap
> /dev/sda2           123      1704  12707415    5  Extended
> /dev/sda5           123       730   4883728+  83  Linux
> /dev/sda6           731      1095   2931831   83  Linux
> /dev/sda7          1096      1217    979933+  83  Linux
> /dev/sda8          1218      1704   3911796   82  Linux swap
> 
> So when I do mkswap:
> 
> # mkswap  /dev/sda8
> /dev/sda8: No such device or address
> 
> So my question: without rebooting how do I get the kernel to reread the 
> partition.  Need I mention this is the boot disk so I can't unmount it.
> 

This is why God invented LVM...

regards

Andrew