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.\" $MidnightBSD$ |
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.\" Copyright (c) 1980, 1991, 1993 |
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.\" The Regents of the University of California. All rights reserved. |
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.\" |
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.\" SUCH DAMAGE. |
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.\" |
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.\" From: @(#)swapon.8 8.1 (Berkeley) 6/5/93 |
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.\" $MidnightBSD$ |
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.\" $FreeBSD: stable/10/sbin/dumpon/dumpon.8 306983 2016-10-10 16:17:14Z sevan $ |
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.\" |
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.Dd May 12, 1995 |
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.Dd October 3, 2016 |
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.Dt DUMPON 8 |
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.Os |
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.Sh NAME |
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.Nm |
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.Op Fl v |
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.Cm off |
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.Nm |
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.Op Fl v |
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.Fl l |
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.Sh DESCRIPTION |
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The |
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.Nm |
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variable in the boot time configuration file |
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.Pa /etc/rc.conf . |
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.Pp |
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< |
For most systems the size of the specified dump device must be at |
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The default type of kernel crash dump is the mini crash dump. |
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Mini crash dumps hold only memory pages in use by the kernel. |
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Alternatively, full memory dumps can be enabled by setting the |
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.Va debug.minidump |
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.Xr sysctl 8 |
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variable to 0. |
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.Pp |
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For systems using full memory dumps, the size of the specified dump |
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device must be at |
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least the size of physical memory. |
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Even though an additional 64 kB header is added to the dump, the BIOS for a |
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platform typically holds back some memory, so it is not usually |
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necessary to size the dump device larger than the actual amount of RAM |
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available in the machine. |
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.Pp |
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The |
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Also, when using full memory dumps, the |
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.Nm |
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utility will refuse to enable a dump device which is smaller than the |
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total amount of physical memory as reported by the |
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variable. |
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.Pp |
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The |
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.Fl l |
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flag causes |
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.Nm |
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to print the current dump device or _PATH_DEVNULL ("/dev/null") if no device is |
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configured. |
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.Pp |
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The |
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.Fl v |
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flag causes |
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.Nm |
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on |
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.Pa /dev/null |
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and thus instructs the kernel not to save crash dumps. |
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.Pp |
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Since |
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.Nm |
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cannot be used during kernel initialization, the |
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.Va dumpdev |
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variable of |
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.Xr loader 8 |
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must be used to enable dumps for system panics which occur |
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during kernel initialization. |
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.Sh FILES |
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.Bl -tag -width "/dev/{ad,da}?s?b" -compact |
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.It Pa /dev/{ad,da}?s?b |
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.Bl -tag -width "/dev/{ada,da}?s?b" -compact |
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.It Pa /dev/{ada,da}?s?b |
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standard swap areas |
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.It Pa /etc/rc.conf |
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boot-time system configuration |
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.Xr rc.conf 5 , |
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.Xr config 8 , |
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.Xr init 8 , |
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.Xr loader 8 , |
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.Xr rc 8 , |
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.Xr savecore 8 , |
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.Xr swapon 8 , |
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The |
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.Nm |
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utility appeared in |
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.Fx 2.1 . |
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.Fx 2.0.5 . |
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.Sh BUGS |
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Because the file system layer is already dead by the time a crash dump |
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is taken, it is not possible to send crash dumps directly to a file. |
