topic Re: logical volume in Operating System - HP-UX

logical volume

Asad Malik — Thu, 28 Mar 2002 20:04:15 GMT

/dev/vg01/u01 2220032 1647617 549445 75% /u01
I have /u01 file system as above. i want to add two more disks to the system and mirror them, create a new volume group on them and a new logical volume. i want to mount this new logical volume on the the mount point /u01/newdir
i shall create newdir. Is that feasible or can not be done. Any issue i should expect
Thanks

Re: logical volume

Clemens van Everdingen — Thu, 28 Mar 2002 20:06:17 GMT

Hi,

Looks like this is possible.
I would not know why not.

C.

Re: logical volume

Sandip Ghosh — Thu, 28 Mar 2002 20:08:29 GMT

It is feasible, but you need not to create another volume group. Just split the mirror and mount the mirror copy on a new directory.

Sandip

Re: logical volume

Asad Malik — Thu, 28 Mar 2002 20:11:06 GMT

/dev/vg01/u01 2220032 1647617
549445 75% /u01
This is not mirrored. only /u01/newdir will be mirrored on the new disks..

Re: logical volume

Christopher McCray_1 — Thu, 28 Mar 2002 20:11:43 GMT

Hello,

Yes indeed it's possible. create the newdir under /u01 and mount it after the vg/lv is created. Just remember that you will have to unmount the /u01 filesystem before unmounting the /u01/newdir filesystem (trivial, but possible) if needed.

Good luck

Chris

Re: logical volume

Asad Malik — Thu, 28 Mar 2002 20:15:34 GMT

"Just
remember that you will have to
unmount the /u01 filesystem
before unmounting the
/u01/newdir filesystem (trivial,
but possible) if needed. "
Will this be other way around/ unmount /u01/newdir first and then /u01

Re: logical volume

Jeff Schussele — Thu, 28 Mar 2002 20:15:49 GMT

I see no problems with your logic here at all. The only caveat would be if your LV that contains /u01 is not mirrored & you lose the drive you'll lose the mount point for /u01/newdir. Moral => mirror all the way down the tree.

Rgds,
Jeff

Re: logical volume

Helen French — Thu, 28 Mar 2002 20:18:09 GMT

Hi Asad,

It is possible to do that. Some points:

1) In any case, if /u01 not available ( a disk fail ?), there will be problems with the new file system ( as the mount directory not available) and thereby causing problems to two different file systems !

2) While backing up, if you need /u01 only you have to unmount this new file system.

3) If you need to unmount the /u01, you have to do that for /u01/newdir too.

4) mounting order in /etc/fstab

HTH,
Shiju

Re: logical volume

Jeff Schussele — Thu, 28 Mar 2002 20:29:19 GMT

Very good points, Shiju!
I forgot about mount order.

Jeff

Re: logical volume

Asad Malik — Thu, 28 Mar 2002 20:30:42 GMT

so far so good
just confirming the mounting and unmounting order again in /etc/fstab. /u01 will be mounted first and then /u01/newdir.
For unmounting /u01/newdir will be first and then /u01.

Re: logical volume

Helen French — Thu, 28 Mar 2002 20:33:24 GMT

Hi Asad,

Yes you are right ! /u01 should be available whenever you mount some file system on that !

HTH,
Shiju

Re: logical volume

Martin Burnett_2 — Thu, 28 Mar 2002 20:42:11 GMT

Hello Asad,

What everyone is telling you is good advice. There is no problem doing this, but why not create a mount point such as /newdir off of / and then put a soft link at /u01/newdir?

# ln -s /newdir /u01/newdir

This way if /u01 is not available you could still get to your files. And you don't have to worry about those pesky /etc/fstab issues.

Martin

Re: logical volume

Asad Malik — Thu, 28 Mar 2002 20:48:48 GMT

Hi Martin
I was exploring that option, but I have given thought to link option and chances are that we will create the link.
Thanks