Veritas Volume Manager 5.0 Troubleshooting Guide, HP-UX 11i v3, First Edition, May 2008

25Recovery from hardware failure

Recovery from failure of a DCO volume

Note: The procedures in this section depend on the DCO version number. See the

Veritas Volume Manager Administrator’s Guide for information about DCO

versioning.

Persistent FastResync uses a data change object (DCO) volume to perform

tracking of changed regions in a volume. If an error occurs while reading or

writing a DCO volume, it is detached and the badlog flag is set on the DCO. All

further writes to the volume are not tracked by the DCO.

The following sample output from the

vxprint command shows a complete

volume with a detached DCO volume (the TUTIL0 and PUTIL0 fields are omitted

for clarity):

TY NAME ASSOC KSTATE LENGTH PLOFFS STATE ...

dg mydg mydg - - - -

dm mydg01 c4t50d0 - 35521408 - -

dm mydg02 c4t51d0 - 35521408 - -

dm mydg03 c4t52d0 - 35521408 - FAILING

dm mydg04 c4t53d0 - 35521408 - FAILING

dm mydg05 c4t54d0 - 35521408 - -

v SNAP-vol1 fsgen ENABLED 204800 - ACTIVE

pl vol1-03 SNAP-vol1 ENABLED 204800 - ACTIVE

sd mydg05-01 vol1-03 ENABLED 204800 0 -

dc SNAP-vol1_dco SNAP-vol1 - - - -

v SNAP-vol1_dcl gen ENABLED 144 - ACTIVE

pl vol1_dcl-03 SNAP-vol1_dcl ENABLED 144 - ACTIVE

sd mydg05-02 vol1_dcl-03 ENABLED 144 0 -

sp vol1_snp SNAP-vol1 - - - -

v vol1 fsgen ENABLED 204800 - ACTIVE

pl vol1-01 vol1 ENABLED 204800 - ACTIVE

sd mydg01-01 vol1-01 ENABLED 204800 0 -

pl vol1-02 vol1 ENABLED 204800 - ACTIVE

sd mydg02-01 vol1-01 ENABLED 204800 0 -

dc vol1_dco vol1 - - - BADLOG

v vol1_dcl gen DETACHED 144 - DETACH

pl vol1_dcl-01 vol1_dcl ENABLED 144 - ACTIVE

sd mydg03-01 vol1_dcl-01 ENABLED 144 0 -

pl vol1_dcl-02 vol1_dcl DETACHED 144 - IOFAIL

sd mydg04-01 vol1_dcl-02 ENABLED 144 0 RELOCATE

sp SNAP-vol1_snp vol1 - - - -

This output shows the mirrored volume, vol1, its snapshot volume, SNAP-

vol1, and their respective DCOs, vol1_dco and SNAP-vol1_dco. The two

disks, mydg03 and mydg04, that hold the DCO plexes for the DCO volume,