[clug] partition tables in memory

David Collett davico at tpg.com.au
Sat Apr 16 14:54:12 GMT 2005


Come to think of it I think that offset number is wrong, but you get the
idea...

Dave

On Sun, 2005-04-17 at 00:42 +1000, David Collett wrote:
> You could do something creative:
> 
> losetup -o $((1218*16065*512)) /dev/loop0 /dev/sda
> mkswap /dev/loop0
> swapon /dev/loop0
> 
> Then, add /dev/sda8 as swap in fstab anyway and next time you reboot, it
> will be used as normal...
> 
> 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
> > 
> 



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