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Stop and re-sync mirror

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Fernando Boza
Regular Advisor

Stop and re-sync mirror

I have a server with HP-UX 11.11 atached to two storages. I have mirror-ux within storages.

I need shutdown one storage for maintenance and then go on again.

What is the most easy method for stop and resync the mirror?
Robert-Jan Goossens
Honored Contributor

Re: Stop and re-sync mirror

Hi Fernando,

Have a look at this white paper and check if you have next patches installed.

For 11.11: Patches PHKL_31216 and PHCO_30698 (or superseding patches)

Steven E. Protter
Exalted Contributor

Re: Stop and re-sync mirror


lvextend -m 0

to break it

lvextend -m 1

to rebuild
rebuild will take some time.

Steven E Protter
Owner of ISN Corporation
sujit kumar singh
Honored Contributor

Re: Stop and re-sync mirror

Hi Fernando,

As a word of caution before doing this i shall suggest you to run the following commands so that you can have the PV list for the existing VG as well as the a map file in place for the VG(s).

for all the VGs that are having the mirrors (MirrorDisk/UX)on both the storages as said by you Ealier, PLease run.

#vgexport -p -v -s -m /tmp/ /dev/

#vgexport -p -v -f /tmp/.Before_Activity.PV_list //dev/

Kepping these map files and the PV list for the involved VGs shall be good.

Acclaimed Contributor

Re: Stop and re-sync mirror

You can simple stop disk access on lvm level with "pvchange -a n ...", see

man pvchange


pvchange -a n /dev/dsk/c3t0d0s2
Warning: Detaching a physical volume reduces the availability of data
within the logical volumes residing on that disk.
Prior to detaching a physical volume or the last available path to it,
verify that there are alternate copies of the data
available on other disks in the volume group.
If necessary, use pvchange(1M) to reverse this operation.
Physical volume "/dev/dsk/c3t0d0s2" has been successfully changed.

Hope this helps!

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Honored Contributor

Re: Stop and re-sync mirror

I may be grossly oversimplifying this, but would not "lvsplit / lvmerge" work for this.

I'm unclear as to whether the original poster was attempting to move data off one storage system to another prior to maint. or if he simply needed to break off the mirrors.....
Armin Kunaschik
Esteemed Contributor

Re: Stop and re-sync mirror

The most easy way is simply do nothing.

In most cases the system will notice that the missing storage is back and start syncing in background.
In all other cases, when the system does not recognize the storage, simply do ioscan and vgsync for any vg with stale extents (or lvsync respectively).

This biggest advantage here is, that you won't need to resync all extents, but only those that changed while the mirror was down.

If, for some unkown reason, none of the mentioned steps work to bring the mirror back online, you're still free to break the mirror, even if the mirror disks are completely gone.

My 2 cents,

PS: Please assign points if you find answers useful!
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