GPT vs MBR for swap devices

bob prohaska fbsd at
Tue Jun 19 06:55:30 UTC 2018

On Tue, Jun 19, 2018 at 07:06:18AM +0300, Jukka Ukkonen wrote:
> Are you sure it is not /usr/obj activity which you are seeing when
> there are large write delays?

I am absolutely not sure. 

> On systems using traditional spinning disks for everything else
> it really makes sense to put /usr/obj on its own SSD making sure
> the SSD does not share an I/O channel with any other device.

Agreed that spreading throughput among channels is good. That's why
I tried to split swap between microSD and USB. The RPI2 systems I've
set up before use a USB flash drive for /usr, /var, /tmp and swap
and they build world successfully. When I set up the RPI3 I thought
it would be an improvement to split the swap between partitions on
microSD and the USB flash drive.

The suspicion I'm harboring is that the swapper on the Pi3 is somehow
confounded by having two separate swap devices. The simplest test I
can easily perform is to use one swap partiton on the microSD card 
and a second swap partition on a separate USB device. To start with
that'll be a mechanical hard disk, which is generally accepted as 

Thanks for reading!

bob prohaska

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