how to return to use multipath device to construct the Vg?
 

Hi,

Here is the situation:
#vgs
vgData 1 7 0 wz--n- 1024.00G 25.00G
#pvs
/dev/sdh vgData lvm2 a-- 1024.00G 25.00G

and now the vg is in use and hundreds of Gigabytes data reside on it.

But I find the server is also using multipath:
# for c in {b,d,f,h}; do scsi_id -gus /block/sd$c; done
360002acac00000000000012c000047e0
360002acac00000000000012c000047e0
360002acac00000000000012c000047e0
360002acac00000000000012c000047e0

so this means sdh is just one of the 4 paths.

Now I want to return to use multipath device to construct the Vg, how to do this?

Thanks in advance.

Is multipathd running?

If so what is the output of "multipath -l -v2" showing you?

The way LVM works is it scans devices to determine what device has the VG information. If pvs is only showing you one path it seems likely you don't have multipathd running so it isn't really treating it as an mpath device.

The multipath devices should be in /dev/mpath (and /dev/mapper usually).

Hi,

Yes, Multipathd is running, and currently have one multipath device: mpath0. I think someone create pv /dev/sdh by mistake(he just used one of the paths to create pv). So I want to know how to revert it.

Since it scans the disk at boot it seems it should find the mpath device automatically and show that as the PV.

Does mpath0 show sdh as one of the component disks? What are the other component disks for mpath0?

In multipath.conf you can exclude certain types of disks so it is possible mpath0 has nothing to do with the disk you're looking at. You can run fdisk -l to see the details of each disk you are looking at to insure they show the same information.