Re: zfs-on-root, missing swap (fixed subject)

On 5/24/23 10:54 AM, Matthew Seaman wrote:
> On 24/05/2023 14:20, Steven Friedrich wrote:
>> On 5/24/23 8:59 AM, Steven Friedrich wrote:
>>> Just this morning, I installed 13.2 on a USB 500 GB SSD  I changed 
>>> swap size from 2GB to 128GB.
>>>
>>> Running synth to install kde5, noticed several build fails and synth 
>>> claims swap is n/a.
>>>
>>> Checked both df and mount, no swap shown.  Also swapinfo shows no swap.
>>>
>>> Where did it go?
>
> What's the result of `gpart show /dev/ada0` ?  (Assuming ada0 is the 
> correct device name for your SSD device.)
>
> You should see something like this:
>
> ```
> # gpart show /dev/ada0
> =>       34  976773101  ada0  GPT  (466G)
>          34          6        - free -  (3.0K)
>          40        984     1  freebsd-boot  (492K)
>        1024   16776352     2  freebsd-swap  (8.0G) <<<-----****
>    16777376  959995752     3  freebsd-zfs  (458G)
>   976773128          7        - free -  (3.5K)
> ```
>
> which tells you the allocated swap area is /dev/ada0p2.  You should 
> then be able to add a line in /etc/fstab like so:
>
> /dev/ada0p2 none swap sw 0 0
>
> and then run:
>
> `service swap start`
>
> More complicated setups are possible, like swapping to a gmirror 
> across partitions on two physical drives, or using glabel to name the 
> partition -- useful if you have removable drives that can upset the 
> device numbering.
>
> It's not advisable to swap to a ZFS or to a file held on ZFS: 
> performance will be bad and you run the risk of system lockups where 
> ZFS will demand more swap before it can provide access to the swap area.
>
> 128GB is (I think) the absolute maximum configurable swap size in 
> FreeBSD 13.2 -- generally it's advisable to limit swap to about the 
> same as RAM on systems with more than 4GB RAM.  See tuning(7).
>
>     Cheers,
>
>     Matthew

Thanks for the response.  I already discovered the problem.  I was 
installing from a USB stick, whuch was assigned da0.  When I rebooted, I 
pulled that and the SSD became da0, instead of da1.

All I had to do was edit /etc/fstab and change da1p3 to da0p3. 8o)

I also re-installed because it was complaining about swap size. I 
re-installed with only 64GB swap.

-- 
FreeBSD freebsd.friedrich.org 13.2-RELEASE FreeBSD 13.2-RELEASE releng/13.2-n254617-525ecfdad597 GENERIC amd64