topic Re: removing volume groups in Operating System - Linux

removing volume groups

Steven Boyer — Fri, 22 Aug 2008 13:57:30 GMT

I need to remove all our volume groups and any association to that VG, so that we can reuse the Hexnumber. will vgexport

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 14:50:22 GMT

reuse the hex number? are you using hp-ux? anyway you can use vgexport on inactive vg's.

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 15:11:53 GMT

yes we need all references to the hexnumber removed so that we can use it again with the same or a different device. when we try to use a hexnumber that is NOT listed in the /dev/*/groups, using vgcreate we get an error that the number is already in use.

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 15:19:21 GMT

Are you sure that is the exact error? I would assume you just have maxvgs in the kernel set to low.

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 15:28:52 GMT

yes we are using a hexnumber that we used successfully before and did a vgremove and tried to use that number again.

exact error "volume group /dev/vg_testsize could not be created: A volume group is already using this major and minor number please check the minor number of the "group" device file.

We checked /dev/*/groups prior to doing mkdir and mknode and that number did not exist. the mknode allowed us to use it the error came with the vgcreate

the maxvgs=80
x04a0000 is 74 and with in range.

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 15:38:57 GMT

try vgexport -f vgnname.

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 15:47:46 GMT

-f is for output file

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 15:52:34 GMT

Sorry, i get used to -f meaning force in other commands. just try the vgexport vgname. if that doesn't work try this:

mv /etc/lvmtab /etc/lvmtab.old
vgscan -v

now try vgcreate again.

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 15:55:55 GMT

im a little reluctant to to mv the lvtab file and run vgscan.... what will that do to existing VG that are already mounted and serving data

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 15:58:34 GMT

it's just going to recreate the file. it's not going to change data in the vg areas on disk. and that is the reason i put the steps to make the backup in the case it doesn't work. I am not offering advice that any other hpux admin wouldn't offer. the choice is yours.

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 16:03:40 GMT

oh and I should mention after looking at it you should use:

vgscan -a -v

sorry

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 16:14:44 GMT

I appreciate the advice, being new to HPUX, Solaris is my background, just want to understand what is going on

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 16:31:11 GMT

No, I understand. You did the first step of making sure there was not a group file with the same minor number. From there you could try vgexport, and then vgscan. You might want to read then man page for vgscan. it makes note to the fact that the device orders may not be the same as they were before, etc. That all really depends on how you setup lvm. if you use multiple luns in a vg and try to spread the load across the luns you will need to clean all that up.

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 16:39:47 GMT

if those options don't work, or you don't want to do the vgscan; you can always reboot. that should clean up the lvm structures in the kernel.

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 17:45:11 GMT

thanks we are running vgscan -a -v -p and it is taking for ever so far 30min is this expected

Re: removing volume groups

Steven Boyer — Fri, 22 Aug 2008 17:45:19 GMT

thanks we are running vgscan -a -v -p and it is taking forever so far 30min is this expected

Re: removing volume groups

Court Campbell — Fri, 22 Aug 2008 18:45:56 GMT

i would assume it could take awhile if you have a large number of devices.