9.1 minimal ram requirements

[Ian Smith]

On Mon, 24 Dec 2012 04:50:22 +1100, Ian Smith wrote:
[following up my own message with a later report]

 > On Sun, 23 Dec 2012 15:21:23 +0300, Sergey Kandaurov wrote:
 >  > On 23 December 2012 10:22, Ian Smith <smithi at nimnet.asn.au> wrote:
 >  > > On Sun, 23 Dec 2012 03:45:39 +0300, Sergey Kandaurov wrote:
 >  > >  > This (i.e. the "kmem_map too small" message seen with kernel memory
 >  > >  > shortage) could be due to CAM CTL ('device ctl' added in 9.1), which is
 >  > >  > quite a big kernel memory consumer.
 >  > >  > Try to disable CTL in loader with kern.cam.ctl.disable=1 to finish boot.
 >  > >
 >  > > I've just added that, thanks Sergey, but it's sadly not an option for
 >  > > installation.  I guess it's too late for the release notes - which at
 >  > > RC3 made no mention of CAM CTL at all - but it's not yet clear to me
 >  > > whether even 256MB is enough to boot, install and run 9.1 GENERIC?
 >  > 
 >  > If you perform clean installation (e.g. from ISO), you can escape to the
 >  > loader prompt and set the tunable there w/o the need for /boot/loader.conf.
 >  > I experimented with Vbox and AFAIK 256MB was enough even with CAM CTL.
 > 
 > Ah right; I'd booted and installed from memstick, where escape to loader 
 > prompt is not an option.  I'll burn a disc1 and try that with the 128MB 
 > again, and make sure that 256MB is comfortable - after holiday madness.

So I tried again with the 128MB RAM, from a disc1 boot, from loader set 
kern.cam.ctl.disable=1, installed all distributions, no problems; with 
sshd, powerd, no ntpd (laptop had broken NIC then, now fixed), loaded 
acpi_ibm (working well, and suspend and resume finally work reliably out 
of the box, excellent!), top showing 77MB free.  Ran it for over a day 
doing nothing much - resume, browse some stuff, suspend - 77MB free.

With 256MB instead, installed as above _without_ disabling kern.cam.ctl, 
no problems, to another slice.  As an aside, bsdinstall didn't update my 
boot0, leaving the previously installed slice selected on boot, but I'm 
more relieved it didn't mess with it :)  top showed 167MB free, steady.

256MB as above but with kern.cam.ctl.disabled=1, top shows 202MB free. 
202 - 167 = 35MB extra by cam.ctl.  Without cam.ctl, 128 - 77 = 51MB 
used, 256 - 202 = 54MB used, unsure where 3MB went but I'm not worried.

So I'm happy to say that 128MB RAM, with kern.cam.ctl.disabled=1, boots, 
installs and runs 9.1-R fine.  I might even try it on my ancient but so 
far unstoppable 10yrs x24x7 Compaq Armada 1500c, maxed out at 160MB :)

I notice that my previous 202MB free is now down to 6.4MB, with swap 
touched at 336K, that's likely normal; I'll work it a bit harder soon.

It'd be nice if booting from memstick allowed dropping to loader.

cheers, Ian