Re: kernel: warning: total configured swap (493567 pages) exceeds maximum recommended amount

From: bob prohaska <fbsd_at_www.zefox.net>
Date: Tue, 11 Nov 2025 16:30:54 UTC
On Tue, Nov 11, 2025 at 12:45:35PM +0000, void wrote:
> On Mon, Nov 10, 2025 at 05:40:49PM -0800, bob prohaska wrote:
> > On Mon, Nov 10, 2025 at 11:29:10PM +0000, void wrote:
> 
> > > fstab entry for swap is:
> > > /dev/label/growfs_swap  none            swap    sw              0       0
> 
> > I've not seen any recognizable benefit in heeding  that warning, but YMMV
> > I've two Pi2's with 3.6G of swap and one with 1.7G of swap. All misbehave
> > in the same way.
> > 
> > If using USB you could try something like (as root)
> > swapoff /dev/da0s2
> > gpart resize -i 2 -s 1700M /dev/da0s2
> > swapon /dev/da0s2
> 
> I'm thinking maybe raising this as a PR because that swap thing - it came
> as-is, pre-installed. I downloaded the Nov 3rd armv7 snapshot,
> wrote it to mmcsd and it was there. I have no idea how to resize or otherwise
> modify /dev/label/growfs_swap or if it's a device or a file.
> Raising it as a PR because if incorrectly sized by default then that's
> a fault.
> 
> I had planned to remove the above swap entry anyway and instead have
> swap nfs-mounted. it'd be faster than anything local on the rpi2b.
> 

I'm not sure how true that is when using a USB hard disk. On a Pi2/3 I gather
the network adapter is a USB device as well, so both devices compete for USB.
Never tested it myself, however. I will say the Pi4 is a vast improvement.

> > If using microSD I'd be wary of swap; some very mysterious file corruption
> > emerged on a Pi3 which had swap on the microSD. Not your situation, of course,
> > just a cautionary tale.
> 
> It's on the microsd by default for 16:main for armv7 too as per above
> 
> > FWIW there is a random collection of "notes to self" at
> > http://www.zefox.net/~fbsd/
> > It's poorly organized, out of date and at least partly wrong.
> 
> Thanks, I'll have a read.

Happy hunting! When you find things wrong or unclear please point 
them out to me. 

Thanks for writing,

bob prohaska