Solaris: Configuring the Dump Device on VxVM Encapsulated Disks

If you use VERITAS Volume Manager (Symantec) to encapsulate the boot disk of a Solaris system, you may see messages like this on boot:

savecore: no dump device configured
dumpadm: no swap devices could be configured as the dump device

Normally on a Solaris system you would run the following command to correct this:

dumpadm -d swap

to indicate that you want to use the swap device as your dump device.  However, on a system with an encapsulated swap partition, you will see the following message from the above command:

dumpadm: no swap devices could be configured as the dump device

The solution for this is to use the underlying device name instead of 'swap' in the dumpadm command.

Determining the swap device name

If you do not already know the device name, you can determine it using this procedure.  First get the Solaris disk name(s) for the swap devices:

vxprint -ht swapvol

You will see output similar to the following:

...
v swapvol - ENABLED ACTIVE 8389656 ROUND - swap
pl swapvol-01 swapvol ENABLED ACTIVE 8389656 CONCAT - RW
sd rootdg01-01 swapvol-01 rootdg01 45888876 8389656 0 c1t0d0 ENA
pl swapvol-02 swapvol ENABLED ACTIVE 8389656 CONCAT - RW
sd rootdg02-02 swapvol-02 rootdg02 45888876 8389656 0 c1t1d0 ENA

In the above example, the devices c1t0d0 and c1t1d0 contain sub-mirrors of the swap volume.  To determine the swap partition on each of these devices, use the 'prtvtoc' command for the full pathname for the disk you would like to use as your dump device:

prtvtoc -s /dev/dsk/c1t0d0s2

You will see output similar to the following.  Look for the partition with '3' (swap) in the 'Tag' column:

*                          First     Sector    Last
* Partition Tag Flags Sector Count Sector Mount Directory
0 2 00 66447 45888876 45955322
1 3 01 45955323 8389656 54344978
2 5 01 0 71127180 71127179
3 15 01 0 66447 66446
4 14 01 66447 71060733 71127179
6 7 00 54344979 16779312 71124290

This indicates that partition 1 of this disk is used as swap.  So the full pathname of this swap device is:

/dev/dsk/c1t0d0s1

Configuring the dump device

To configure the dump device, issue the 'dumpadm' command with the above device:

dumpadm -d /dev/dsk/c1t0d0s1

The command should will show output similar to the following:

      Dump content: kernel pages
Dump device: /dev/dsk/c1t0d0s1 (dedicated)
Savecore directory: /var/crash/hostname
Savecore enabled: yes

At this point we are almost done.  The system now knows to use our swap partition as a dump device.  However, if the 'Dump device' line shows 'dedicated' as the device type, savecore is allowed to write to this device at any time, which is a problem since the device is shared with swap.

To correct this, run the following command:

/etc/vx/bin/vxswapctl set /dev/dsk/c1t0d0s1

This command marks the device as swap so that savecore will share the device properly.  If you now review your dump configuration:

dumpadm

You should now see the correct configuration:

 Dump content: kernel pages
Dump device: /dev/dsk/c1t0d0s1 (swap)
Savecore directory: /var/crash/hostname
Savecore enabled: yes

with 'swap' now as the 'Dump device' type.