docs/177188: dumpon(8) unaware of mini crash dumps

[Fabian Keil]

>Number:         177188
>Category:       docs
>Synopsis:       dumpon(8) unaware of mini crash dumps
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Mar 21 11:40:01 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Fabian Keil
>Release:        HEAD
>Organization:
>Environment:
FreeBSD r500.local 10.0-CURRENT FreeBSD 10.0-CURRENT #555 r+5b01145: Wed Mar 20 22:01:58 CET 2013     fk at r500.local:/usr/obj/usr/src/sys/ZOEY  amd64

>Description:
dumpon(8) currently states:

| The dumpon utility will refuse to enable a dump device which is smaller
| than the total amount of physical memory as reported by the hw.physmem
| sysctl(8) variable.

If mini crash dumps are enabled smaller dump devices are actually accepted.

It might also be worth mentioning that with mini crash dumps disabled no error message is printed unless -v is used.

>How-To-Repeat:
fk at r500 ~ $sysctl debug.minidump
debug.minidump: 1
fk at r500 ~ $sysctl kern.shutdown.dumpdevname
kern.shutdown.dumpdevname: 
fk at r500 ~ $sysctl hw.physmem
hw.physmem: 2070306816
fk at r500 ~ $diskinfo -v /dev/da0 | grep bytes
	750780416   	# mediasize in bytes (716M)
fk at r500 ~ $sudo dumpon /dev/da0
fk at r500 ~ $echo $?
0
fk at r500 ~ $sysctl kern.shutdown.dumpdevname
kern.shutdown.dumpdevname: da0
fk at r500 ~ $sudo dumpon off
fk at r500 ~ $sudo sysctl debug.minidump=0
debug.minidump: 1 -> 0
fk at r500 ~ $sudo dumpon /dev/da0
fk at r500 ~ $echo $?
74
fk at r500 ~ $sudo dumpon -v /dev/da0
/dev/da0 is smaller than physical memory

>Fix:
Update the man page.

>Release-Note:
>Audit-Trail:
>Unformatted: