Re: install/55375: sysinst sets swap partition size 0 bytes on <800MB disk

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR install/55375; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: install/55375: sysinst sets swap partition size 0 bytes on
 <800MB disk
Date: Mon, 28 Sep 2020 19:31:51 +0200

 On Fri, Jun 12, 2020 at 05:30:00PM +0000, Izumi Tsutsui wrote:
 > DEFUSRSIZE (800MB) seems a size for "Full installation",
 > so it's too aggressive to remove swap partition completely
 > for such full size /usr binaries for users who will install
 > NetBSD using "Minimum installation".
 
 The problem is that we do not (yet) know which sets are going to be installed.
 
 > sysinst also tries to reserve space for root parttion to
 > "add space for 2 system dumps to /" but I doubt it's really
 > useful to reserve such space by "shrinking the swap partition."
 > 
 > Maybe it's better to have a "lower limit" of the default
 > swap partition size?
 
 And the other problem is that we do not currently take into account how
 important swap will be for the installed system.
 
 Maybe we should check for a list of conditions:
 
  - if the target medium is unsuitable for swapping (SD card) drop
    swap completely (we do that for some architectures already)
  - if completely removing swap is not helping much (still too little
    disk space) leave the swap default alone
  - if the system has plenty of RAM (like > 3 GB) set a lower limit of swap
    to deal with a kernel crash dump (depending on sparse crash dumps being
    implemented for the architecture)
  - if the system has very few RAM (like < 300 MB) set a big enough lower swap
    limit
 
 Then in all automatic adjustments hounour the calculated lower swap size limit,
 but still allow the user to manually set it to zero.
 
 I'm open to suggestions for improvements/fine tuning of numbers.
 
 Martin