[EdLUG] Linux hibernate

[Andrew Smith]

Colin
I didn't realise Ubuntu was now 22.04 and the latest kernel was 5.19.
Thanks. I'll upgrade  and hopefully get  what I want.
Can anyone tell me the line I need in /etc/apt/sources.list to download the
source to systemctl
Andrew


On Sat, 17 Sept 2022 at 20:13, Colin Shorts <colin.shorts at gmail.com> wrote:

> Andrew is running a reasonably old kernel (5.4). Trial and error might be
> called for. Perhaps a newer kernel might help too?
>
> On Sat, 17 Sept 2022, 18:48 Roy, <roy at crossford.net> wrote:
>
>> Isn't the hibernate image compressed these days?
>>
>> That means that it might fit with some swap in use. It might not too.
>>
>> Regards,
>>
>> Roy Bamford
>>
>>
>>
>> On 17/09/2022 16:50, Geetam wrote:
>>
>> I only know the theory of hibernating, so please fill in a bit of
>> hibernating knowledge that I do not have. (I am so old-fashioned that I
>> shut down and boot up 😬 )
>>
>> When hibernating, the state of internal memory is stored on disk. Linux
>> uses the swap partition on disk for this. So your swap partition needs to
>> be large enough, i.e. at least as large as your internal memory - in your
>> case 32Gb
>>
>> BUT WHAT HAPPENS when you have so much open on your desktop that your
>> internal memory wasn't big enough and some of the less active processes
>> have been swapped to swap space? (I am sure most of us avoid that, but that
>> is what swap space is for, isn't it?)
>>
>> Say you have 40GB in use (32Gb in internal memory, 8Gb swapped to swap
>> space). Is hibernating going to try to save 40GB into swap space? That
>> won't fit into the 32Gb swap partition... Or is it only writing the 32Gb in
>> internal memory to the swap partition clobbering the 8Gb that was there?
>> Then the full state of your desktop cannot be restored.
>>
>> Is this maybe why Andrew is not able to hibernate?
>>
>> I am sure someone in the Linux world has thought about this, but I think
>> we have forgotten because we try to have so much internal memory that swaps
>> space is not used and the issue hardly ever arises these days. Still, I am
>> curious 🤔
>>
>> Regards
>> Geetam
>>
>> --
>> I don't know
>> ...
>> I don't know what it is
>> ...
>> I don't know what it is that I don't know
>>
>> Isn't it beautiful
>>
>>
>> On Fri, 16 Sept 2022 at 08:04, Colin Shorts <colin.shorts at gmail.com>
>> wrote:
>>
>>> Hi Andrew, I'd be inclined to add a smidgen more swap to be on the safe
>>> side.
>>>
>>> I take it `sudo pm-hibernate` doesn't work (correctly) either? Are the
>>> kernel parameters getting set at boot (I think dmesg should say which
>>> device will be used)? Is your swap partition on lvm, are you mounting it
>>> using the uuid?
>>>
>>> I'm in the middle of redecorating my home office or I'd give it a bash
>>> myself 😃
>>>
>>> Cheers,
>>> Colin
>>>
>>> On Fri, 16 Sept 2022, 01:16 Andrew Smith, <asmith9983 at gmail.com> wrote:
>>>
>>>> Hi Colin
>>>> I have 32Gb of swap, with *htop* reporting  none used in normal
>>>> operation.
>>>> Suspend works OK. Given the minimal energy consumed overnight on
>>>> suspend, I may just continue using that until I can investigate further
>>>> how  *suspend-then-hibernate* is meant to operate by reading the
>>>> sourcecode of *systemctl. *
>>>> Andrew
>>>>
>>>>
>>>> On Wed, 14 Sept 2022 at 20:07, Colin Shorts <colin.shorts at gmail.com>
>>>> wrote:
>>>>
>>>>> I'm no expert on hibernate (I use suspend myself), but iirc you'll
>>>>> need at least as much free swap as system ram +used swap. 64GB doesn't
>>>>> sound unreasonable as a starting point assuming you've got enough space and
>>>>> considering how much Chrome can chew up.
>>>>>
>>>>> -Colin
>>>>>
>>>>> On Wed, 14 Sept 2022, 18:03 Andrew Smith, <asmith9983 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Guys
>>>>>> For quite a while, I've been putting my system into suspend mode,
>>>>>> which was successful , apart from an odd occassion.  I now want to try
>>>>>> saving more energy
>>>>>> I've tried powering down, but would like it to restart in the same
>>>>>> state rather than with a new login, as I had with suspend.
>>>>>> I've tried "systemctl suspend-then-hibernate" from root CLI, but  I
>>>>>> get essentially  a fresh boot.
>>>>>>
>>>>>> Any suggestions ?
>>>>>> I'm running kernel 5.4.0-125-generic from Ubuntu, in 32Gb RAM, and
>>>>>> typically have a around hundred tabs open on Chrome.
>>>>>> Andrew
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>>>>>>
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