pkg upgrade, vm.pageout_oom_seq: swap off: UFS, ZFS

From: Graham Perrin <grahamperrin_at_gmail.com>
Date: Thu, 04 Sep 2025 00:14:24 UTC
On 02/09/2025 19:19, Mark Millard wrote:

> On Aug 31, 2025, at 12:01, Graham Perrin <grahamperrin@gmail.com> wrote:
>
>> …
> The notes here are about the following sequence of 4 commands:
>
>> pkg install -Fy firefox gitup htop hw-probe kde lsblk lynx nano pciutils plasma6-sddm-kcm roxterm sddm stressdisk uclcmd usbutils virtualbox-ose-additions xfce xorg
>> pkg install -Uy firefox gitup htop hw-probe kde lsblk lynx nano pciutils plasma6-sddm-kcm roxterm sddm stressdisk uclcmd usbutils virtualbox-ose-additions xfce xorg
>> pkg upgrade -fFqy
>> pkg upgrade -fUy
> In a 14.3-Stable amd64 UFS context the above command sequence:
>
> 1) Will probably OOM on a system with 1 GiByte of RAM but no swap space,
>     even for the first install command.
>
> 2) The sequence of 4 commands used (RAM+SWAP):
>     1024 MiBytes + 2312 MiBytes (observed maximum)
>     (So between 3 and 4 GiBytes of RAM+SWAP overall.)
>
> 3) So  will OOM on a system with 2 GiByte of RAM but no swap space,
>     overall.
>
> …


Here, with 3 G, fast storage, and swap off: UFS and ZFS seemed much the 
same.

RELEASE, quarterly.


UFS (dmesg: 2928 MB avail memory)
=================================

Fourth command (pkg upgrade -fUy).

First run failed. vm.pageout_oom_seq=120

Second and third runs (not consecutive to the first): success. For the 
third run, I reduced vm.pageout_oom_seq to its default (12).


ZFS (dmesg: 2920 MB avail memory)
=================================

Four consecutive runs of the fourth command.

Two runs with vm.pageout_oom_seq=120: success. Third and fourth runs 
with vm.pageout_oom_seq=12:

- the third run failed almost immediately, before step 1 of 2601

- the fourth run succeeded.