[clug] partition tables in memory

[David Collett]

man hdparm reveals:

       -z     Force a kernel re-read of the partition table of  the
specified device(s).

However I'm pretty sure fdisk would do the same thing (send an ioctl or
whatever) when you exit, so that may not help you.

Dave


On Sat, 2005-04-16 at 17:02 +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.
> 
> 
> Kim
> 
> On 2005 Apr 16, , at 2:36 PM, Kim Holburn wrote:
> 
> > Hi,
> >
> > I have a linux server which needed more swap.  I added a new swap 
> > partition wrote the new partition table but it doesn't show up in 
> > /proc/partitions so I can't mkswap etc.
> > # mkswap  /dev/sda8
> > /dev/sda8: No such device or address
> >
> > Is there any way to get the kernel to reread the partition table or do 
> > I have to do the windows thing and reboot (and lose my uptime;-( )?
> >
> > Dell debian stable kernel 2.4.26 #1 SMP
> >
> > Kim
> > -- 
> > Kim Holburn
> > Network Manager,  National ICT Australia Ltd.
> > Ph: +61 2 61258620 M: +61 417820641 F: +61 2 6230 6121 aim://kimholburn
> > Email: kim.holburn at anu.edu.au  - PGP Public Key on request  
> > callto://kholburn
> > Cacert Root Cert: http://www.cacert.org/index.php?id=16 -> 
> > http://www.cacert.org/cacert.crt
> > Aust. Spam Act: To stop receiving mail from me: reply and let me know.
> >
> > Use ISO 8601 dates [YYYY-MM-DD] 
> > http://www.saqqara.demon.co.uk/datefmt.htm
> > Democracy imposed from without is the severest form of tyranny.
> >                           -- Lloyd Biggle, Jr. Analog, Apr 1961
> >
> > -- 
> > linux mailing list
> > linux at lists.samba.org
> > https://lists.samba.org/mailman/listinfo/linux
> >
> -- 
> Kim Holburn
> Network Manager,  National ICT Australia Ltd.
> Ph: +61 2 61258620 M: +61 417820641 F: +61 2 6230 6121 aim://kimholburn
> Email: kim.holburn at anu.edu.au  - PGP Public Key on request  
> callto://kholburn
> Cacert Root Cert: http://www.cacert.org/index.php?id=16 -> 
> http://www.cacert.org/cacert.crt
> Aust. Spam Act: To stop receiving mail from me: reply and let me know.
> 
> Use ISO 8601 dates [YYYY-MM-DD] 
> http://www.saqqara.demon.co.uk/datefmt.htm
> Democracy imposed from without is the severest form of tyranny.
>                            -- Lloyd Biggle, Jr. Analog, Apr 1961
>