The amazing dissapearing Logical volume

[u856100]

Guys,

I am currently trying to uncover the mystery of three logical volumes that are missing from my system. Sam acknowledges that they are there, but cannot see the mount points. My fstab does not indicate their existence, and there are no missing peripherals from the setup. It all seems a bit weird?

The volume group consists of four 2gig disks, 2 of which have Oracle installed, spread over two logical volumes.

I was curious as to whether there is some sort of history log that I can look in to check of their existence.

thanks for any suggestions whatsoever!

John

[Thierry Poels_1]

Hi,

is it possible this are raw volumes used for Oracle data??
Oracle can use raw devices instead of cooked filesystems (with ordinary directories and files) for high performance. In this case you will not find any references in /etc/fstab. Check with your DBA.

regards,
Thierry.

[Rainer von Bongartz]

Looks like you got raw volumes therer with no file system on it.

You wont't seee theese volumes with tools that look for file systems.

Try vgdisplay -v instead

Regards
rainer

[Volker Borowski]

Hi,

switch to oracle user and do

svrmgrl
connect internal
select * from dba_data_files;
select * from v$datafile;
select * from v$controlfile;
select * from v$logfile;

Check out if the names listed refer to your raw logical volumes or to links that point to these volumes. If yes, Oracle is using these volumes directly, if not, they might have been created and even mounted, but not enterd into the fstab-file.

Volker

[u856100]

Hi Gents,

thanks for your suggestions.
There are no raw file systems used by Oracle and I can see the allocated Logical volume groups i.e. :

in sam 'Disks and File Systems'

Name MB available PV's LV's
--------------------------------------
vg00 164 of 2044 1 8
vg01 0 of 8128 4 5

and

#pvdisplay -v vg01 produces :

Volume groups --

Cur LV 5

[Rainer von Bongartz]

what's the output of

vgdisplay -v vg00
vgdisplay -v vg01


Regards
Rainer

[u856100]

I have just checked the tables mentioned above for mount points of the dbf's ctl's etc.

These are all fine and belong to a visible volume group.

I am pretty sure this is not an Oracle problem but something simpler regarding system setup.

The only thing that has happened recently is a power cut where my machine was killed (only a workstation and hash unit so no UPS). I have rebooted since then, about 4 times, but still no lost LV's

hmmmm

[u856100]

Sorry, forgot to mention that vg00 is fine and is only recording the standard 8 LV's

cheers

John

[Kenny Chau]

First, you can do an ioscan on the disk:

# ioscan -fnC disk

Check that all the disk are there and check the device file, ie. /dev/dsk/cXtXdX and /dev/rdsk/cXtXdX

If they are all there, do an vgdisplay

# vgdisplay -v /dev/vg00
# vgdisplay -v /dev/vg01

Check that the how many disks are in the VG and check how many LVs are in 1 VG. Calculate the PEs from the output to see if it matched.

Try to mount the missing LVs to a temp mount point to see if you can mount the LVs.

Have you reboot your server before? If you had reboot your server and did not add the FS in the fstab, it will not mount it after reboot.

Hope this helps.
Kenny.

[Carlos Fernandez Riera]

1- first thing i do is try to mount them:

mount /dev/vgxx/lvolmissing1 /tmp_mnt

Try with diferent options too:


mount -F HFS /dev/vgxx/lvolmissing1 /tmp_mnt


If it can be mounted then , just see what files contain and maybe you can known what s that.


If you cannot mount go to step 2:

2- dd if=/dev/vgxx/rlvolxx of=/tmp/test1 bs=1024k count=1

strings /tmp/test1 | head -10

If it was a oracle datafile you should see:

Z[\]

followed by a ORACLE_SID.

HTH