Resume device. What is it?

Tue Mar 31 14:09:31 UTC 2009

2009/3/31 Howard Coles Jr. <dhcolesj at gmail.com>:
> On Monday 30 March 2009 01:20:04 pm Nigel Henry wrote:
>> On Monday 30 March 2009 18:52, Antonio Augusto (Mancha) wrote:
>> > Hey Nigel,
>> >
>> > For what i get your problem MIGHT be, indeed, related to UUID. UUID is
>> > used as a "symbolic" name to a device, so you ca use it instead of
>> > /dev/sda3 (which might change when you repartition your disk).
>> > What might be happening is that the UUID of /dev/sda3 was changed
>> > (maybe by the new install of F10?) and hence none of your OSs can find
>> > it. You can check this by looking at /dev/disk/by-uuid and seeing if
>> > there is a syn-link there pointing to /dev/sda3, if there is check if
>> > its the same name as used in /etc/fstab.
>> >
>> > The reason you see 0Mb swap may be because the UUID can't be found,
>> > and hence no swap is activated.
>> >
>> > To your other question: yes you can simple comment that line in fstab
>> > and replace it with the one form arch.
>> >
>> > Also, then you see "resume device", usually it refers to the partition
>> > used to store the contents of the RAM when you put your computer to
>> > hibernate (suspend do disk). Linux uses the swap space to store the
>> > contents of the RAM, so it can resume when booted.
>> > When you see a message like "waiting for resume device" or "resume
>> > device not found", it simply means that Linux was not suspended to
>> > disk, and is doing a cold boot. Nothing wrong with that.
>> >
>> > If you have any more questions please post them.
>> >
>> > Cheers,
>> > KM
>>
>> Hi Antonio.
>>
>> Thanks for your reply. Having booted up a few other distros on this
>> machine, so as to post output on my previous post to the list, I've just
>> tried F10 again, which now boots up ok (No real surprise, as I often have
>> problems with this Asus M2N-X Plus mobo). That said, fstab output from F10
>> is below, and /, and /home have UUID's, but swap is accessing /dev/sda3,
>> and Gkrellm is showing 2000M-2000M free, which is correct. F10 was the last
>> distro installed on this machine.
>>
>> #
>> # /etc/fstab
>> # Created by anaconda on Mon Feb 16 21:08:47 2009
>> #
>> # Accessible filesystems, by reference, are maintained under '/dev/disk'
>> # See man pages fstab(5), findfs(8), mount(8) and/or vol_id(8) for more
>> info #
>> UUID=bd4e6a39-e802-44d4-9fd0-fc22692770b0 /                       ext3
>> defaults        1 1
>> UUID=5d6d96b6-c815-4816-8bce-81c286210754 /home                   ext3
>> defaults        1 2
>> tmpfs                   /dev/shm                tmpfs   defaults        0 0
>> devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
>> sysfs                   /sys                    sysfs   defaults        0 0
>> proc                    /proc                   proc    defaults        0 0
>> /dev/sda3               swap                    swap    defaults        0 0
>>
>> /dev/sdb1               /mnt/sdb1               vfat    auto,umask=0    0 0
>> /dev/sdb2               /mnt/sdb2               vfat    auto,umask=0    0 0
>>
>>
>>
>> Now a reboot into Kubuntu Intrepid 8.10, and with an edit to fstab,
>> changing the UUID for swap to /dev/sda3, this appears to be ok after a
>> reboot. See below for fstab output.
>>
>> # /dev/sda3
>> #UUID=a2bc95ec-5fe4-4651-9ca5-7027344141e3 none            swap    sw
>> 0       0
>>
>> #Swap reference changed by me
>> /dev/sda3             none           swap           sw       0 0
>>
>> The above appears to have resolved the problem. On bootup with Intrepid,
>> the bootup still hangs at the "waiting for resume device" line for a couple
>> of seconds, but I'll let that go. At least Gkrellm now shows that swap is
>> on.
>>
>> Tried sudo swapoff /dev/sda3, and Gkrellm showed swap as 0M, then did sudo
>> swapon /dev/sda3, and Gkrellm showed swap as 2000M-2000M free.
>>
>> Thanks again for your reply Antonio.
>>
>> Nigel.
>>
>> > On Mon, Mar 30, 2009 at 13:26, Nigel Henry <cave.dnb2m97pp at aliceadsl.fr>
>>
>> wrote:
>> > > I booted up F10 this morning, after fixing an selinux related problem
>> > > yesterday, but the bootup stalled. I noticed an entry on the bootup
>> > > messages, "unable to stat resume device". Not wishing to waste time on
>> > > F10, as I'd had enough of that yesterday, I rebooted to Kubuntu
>> > > Intrepid (on the same machine), and Intrepid hung for a few seconds
>> > > with "waiting for resume device", then the bootup continued with no
>> > > problems.
>> > >
>> > > I googled "resume device", and there are a whole bunch of hits, with
>> > > folks having various problems with it. It appears to be referencing
>> > > "swap", but why resume device. I would have thought that, that
>> > > description applied more to laptops, and my machine is a PC.
>> > >
>> > > Nigel.
>
> Nigel, look in the boot.cfg or /boot/grub/menu.lst for an entry called
> "resume=<some device>"  Make it match either with the UUID or the /dev/ id
> name and you should be good or just remove it altogether (as mine is) and the
> OS should find it by default.  This entry tells the Kernel were to look for a
> resumable instance of the OS whether to RAM (suspend) or to Disk (Hibernate).

i believe this entry is in "/etc/initramfs-tools/conf.d/resume"
i've had to edit this file many times, nowadays i use a link from
/dev/disk/by-id in that file, since i always run mkswap which changes
my swap's UUID.

-- 
Willy K. Hamra
Manager of Hamra Information Systems
Co. Manager of Zeina Computers and Billy Net.