Re: My "swap" space seems to have vanished....

[DB]

On 03/18/2011 04:42 PM, [e-mail] wrote:
> Subject:
> Re: My "swap" space seems to have vanished....
> From:
> "Michael D. Setzer II" 
> Date:
> Sat, 19 Mar 2011 01:42:33 +1000
>
> To:
> Martin Airs , [e-mail]
>
> On 18 Mar 2011 at 15:34, Martin Airs wrote:
>
> From:	Martin Airs
> To:	[e-mail]
> Subject:	Re: My "swap" space seems to have vanished....
> Date sent:	Fri, 18 Mar 2011 15:34:10 +0000
> Send reply to:	Martin Airs,
>    Community support for Fedora users
>    
> > > On Friday 18 Mar 2011 14:46:23 DB wrote:
> > > > > df
> > > > >
> > > > > Filesystem           1K-blocks      Used Available Use% Mounted on
> > > > >  /dev/sda2             28833848   5518600  23022388  20% /
> > > > >  tmpfs                  1899484      1068   1898416   1% /dev/shm
> > > > >  /dev/sda1               474440     50462    399481  12% /boot
> > > > >  /dev/sda3            288370940  26611056 247111416  10% /home
>
> Your swap is part of the LVM partitions.

I don't have LVM partitions - at least, I never set any up!!!
> cat /proc/partitions
>
> On mine it shows
> major minor  #blocks  name
> 8        0  488386584 sda
> 8        1     204800 sda1
> 8        2   32696288 sda2
> 8        3  455482912 sda3
>
> 253        0   27123712 dm-0
>   253        1    5570560 dm-1
>
> In this case dm-1 is the swap partition.
>
> swapon -s shows the status of the swap.
>
> On my system.
> Filename		Type		Size	        Used	  Priority
> /dev/dm-1           partition	5570556	2156	     -1

Yes, mine is similar
  swapon -s
Filename                       Type            Size    Used    Priority
/dev/sdb5                    partition       2047996     0       -1
> > > df -h on my system doesn't show swap either
> > >
> > > [martin@desktop ~]$ df -h
> > >  Filesystem            Size  Used Avail Use% Mounted on
> > >  /dev/mapper/VolGroup-lv_root
> > >                          22G   20G  904M  96% /
> > >  tmpfs                1005M  3.3M 1001M   1% /dev/shm
> > >  /dev/sda1             194M   62M  123M  34% /boot
> > >  /dev/mapper/VolGroup-lv_home
> > >                          50G   38G  9.5G  80% /home
> > >  /dev/sdb1             112G   95G   18G  85% /media/disk
> > > > > Dave
> > > > >
> > > > > uname -ar
> > > > >  Linux Fedora-Blue 2.6.35.11-83.fc14.x86_64 #1 SMP Mon Feb 7 07:06:44 UTC
> > > > >  2011 x86_64 x86_64 x86_64 GNU/Linux
> > >
> > > however if i type free -m
> > >  [martin@desktop ~]$ free -m
> > >                total       used       free     shared    buffers     cached
> > >  Mem:          2008       1759        248          0        100        585
> > >  -/+ buffers/cache:       1073        934
> > >  Swap:         3967         16       3951
> > >
> > > my swap is indeed there, does free show swap on your system??

Indeed:
free -m
             total       used       free     shared    buffers     cached
Mem:         3709       2013       1696          0        102       1139
-/+ buffers/cache:        770       2939
Swap:         1999          0       1999
> > > Martin

Thanks all for the many suggestions!

Strangely, just after I sent my original mail, System Monitor suddenly 
decided, all on its own, to add the 2GB swap partition....???????  I
think I must have a Gremlin somewhere!

Anyway, things appear to be (back to) "normal"!

Thanks again

Dave

My "swap" space seems to have vanished....

[Joel Rees]

On Sat, Mar 19, 2011 at 9:24 PM, DB  wrote:
> On 03/18/2011 04:42 PM, [e-mail] wrote:
> > Subject:
> > Re: My "swap" space seems to have vanished....
> > From:
> > "Michael D. Setzer II" 
> > Date:
> > Sat, 19 Mar 2011 01:42:33 +1000
> >
> > To:
> > Martin Airs , [e-mail]
> >
> > On 18 Mar 2011 at 15:34, Martin Airs wrote:
> >
> > From: Martin Airs
> > To:   [e-mail]
> > Subject:      Re: My "swap" space seems to have vanished....
> > Date sent:    Fri, 18 Mar 2011 15:34:10 +0000
> > Send reply to:        Martin Airs,
> >       Community support for Fedora users
> >       
> >      
> > > > On Friday 18 Mar 2011 14:46:23 DB wrote:
> > > > > >     df
> > > > >  >  Filesystem           1K-blocks      Used Available Use% Mounted on
> > > > >  >  /dev/sda2             28833848   5518600  23022388  20% /
> > > > >  >  tmpfs                  1899484      1068   1898416   1% /dev/shm
> > > > >  >  /dev/sda1               474440     50462    399481  12% /boot
> > > > >  >  /dev/sda3            288370940  26611056 247111416  10% /home
> > > > >  >
> >
> > Your swap is part of the LVM partitions.
>
> I don't have LVM partitions - at least, I never set any up!!!

That should have been, "either LVM (managed) or (within a) DOS
Extended partition".

The basic (or, "physical") DOS partitioning scheme was invented when
hard disks were relatively small and DOS was really limited anyway,
and it was assumed that it would not form the basis of any serious OS.
(Serious and deliberate lack of foresight on the part of one of the
now richest men in the world.)

So somebody invented a scheme of extending the basic DOS partition
map, but only one partition could be extended that way. I looked back
up in the thread, and that was partition 4 in yours.

Probably, when you were setting up your partitions, gparted told you,
"You can't have more than that without making an extended (DOS
extended, or, "logical") partion." and you did that without thinking
too hard about it.

LVM ("Logical Volume Manager") partitions can also be made in
something the same way, but the prompts that get you there are a
little more noticeable. Also, you can have more than one DOS BASE
partition on a drive be managed by LVM if you want to. (NOT
recommended! although I have done that for multi-booting purposes.)

But, yeah, your swap is not LVM managed. It's within a DOS
extended/logical partition.
> Strangely, just after I sent my original mail, System Monitor suddenly
> decided, all on its own, to add the 2GB swap partition....???????  I
> think I must have a Gremlin somewhere!

The gremlin you are thinking of was probably a stuck event queue, and
calling swapon may have (indirectly?) cleared it.

--
Joel Rees