geli'd swap and core dumps

[jhell]

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On 09/05/2010 03:56, Carl wrote:
> I would like to encrypt my swap partition like Pawel does on his
> company's production servers:
> 
> 
> http://blogs.freebsdish.org/pjd/2010/08/06/from-sysinstall-to-zfs-only-configuration/
> 
> 
> Does Pawel's method result in kernel panics having no functional dump
> device?
> 
> What are best practices for achieving encrypted swap and functional core
> dump recovery? Or are these mutually exclusive goals?
> 

Encrypt your swap let it do its job as a swap device and if you are
planning to gather core dumps you always have the choice of a dedicated
encrypted dumpdev that is not ``onetime'' encrypted.

Personally I use USB dedicated hardware for dumps thumb-drives or
whatever is available at the time and allows me to grab the core from it
after -> analyze it... if its interesting I can pull the dumpdev, label
it and keep it till a time that I deem it recyclable.

Dumps that are being done now are minidump's unless you have chosen to
explicitly do a full dump ``debug.minidump'' so the size of your dumpdev
should be approximate to the size of kmem at the time the dump occurs.
Most times a 1GB flash card or thumb-drive suits this purpose allowing
for a safe amount of room to grow.

Attached is a script that was obtained from one of the ZFS wiki's out
there that calculates and prints out some things about KMEM.

PS: There has also been some work around getting network dumps working
so you may just want to look into that. As for how far along ? I am
unsure. Would be nice to have a central crash dump repository though.


Regards,

- -- 

 jhell,v
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#!/bin/sh -

TEXT=`kldstat | awk 'BEGIN {print "16i 0";} NR>1 {print toupper($4) "+"} END {print "p"}' | dc`
DATA=`vmstat -m | sed -Ee '1s/.*/0/;s/.* ([0-9]+)K.*/\1+/;$s/$/1024*p/' | dc`
TOTAL=$((DATA + TEXT))

echo TEXT=$TEXT, `echo $TEXT | awk '{print $1/1048576 " MB"}'`
echo DATA=$DATA, `echo $DATA | awk '{print $1/1048576 " MB"}'`
echo TOTAL=$TOTAL, `echo $TOTAL | awk '{print $1/1048576 " MB"}'`
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