topic Re: Disk unused in Operating System - HP-UX

Disk unused

Eli Daniel — Thu, 14 Jan 2010 13:21:50 GMT

good morning, before commenting on something I would like to wish you a happy new year.
wanted to know if any of you can help me for a command which are the disks that are unsed (EMC).
according to my supervisor multiple disks found unsed, but they are.
ioscan command with the disk can see the disks but how do I know if they are unused?

Re: Disk unused

James R. Ferguson — Thu, 14 Jan 2010 13:32:11 GMT

Hi Eli:

Documentation is the only sure way to know if a physical disk is "used" or not.

Consider that you can 'vgexport' a volume group. The physical disk aren't "used" by the server, but they could be 'vgimport'ed elsewhere.

Next, a physical disk might be used as a raw device.

From a SAN perspective, a physical disk might not be assigned to any server, but it could still contain valuable data.

Documentation is critical.

Regards!

...JRF...

Re: Disk unused

rariasn — Thu, 14 Jan 2010 13:34:57 GMT

Hi Eli,

# symvg list

rgs,

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 13:36:42 GMT

nnex send the unused disk image

Re: Disk unused

Torsten. — Thu, 14 Jan 2010 13:37:03 GMT

JRF: Documentation is the only sure way to know if a physical disk is "used" or not.

Strongly agree!

Re: Disk unused

Torsten. — Thu, 14 Jan 2010 13:43:44 GMT

"unused" in your screenshot means no LVM or VxVM.

But could be used by database or virtual machines without a volume manager!

Re: Disk unused

TTr — Thu, 14 Jan 2010 13:49:52 GMT

For the unused disks in your server I would check two things. One is if there are multiple paths involved. These LUNs may be in use on this server under a different path.

Second, if these LUNS are not used in this server, you need to unpresent them from this server in EMC. Then you need to check in EMC if these LUNs have been presented to another server and are being used there.

These have commands to cross reference EMC LUNs and HP-UX disks.

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1087725

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1290435

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 13:50:21 GMT

the disk image to a server belonging Virtual Partition. It means that the disk that is "unused" are being used by another machine, or are allocated without being used.

Re: Disk unused

TTr — Thu, 14 Jan 2010 13:57:13 GMT

> the disk image to a server belonging Virtual Partition

Nor sure what you are trying to say here. Is this server a virtual machine or do you have virtual machines in this server? Also as Torsten asked do you have databases that may be using raw volumes? (oracle, RAC, sybase etc)

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 14:02:35 GMT

this is a rx7640 server with 4 Virtual Partition. There are no Virtual Machine.

In the SAP server is installed, if any database but is assigned to another VG (LVM).

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 14:04:46 GMT

Is there any way to know if the disks "unused" contain data?????

Re: Disk unused

Torsten. — Thu, 14 Jan 2010 14:07:24 GMT

Unpresent them and wait if someone complains ...

;-)

More serious - if you don't know what are you looking for you will probably find nothing!

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 14:11:04 GMT

I am looking for help. I need to know whether the disk "unused" are used or not.

Re: Disk unused

Torsten. — Thu, 14 Jan 2010 14:15:38 GMT

I know.

But what to tell?

Disk are not under volume manager control.

Are the disk mounted?

Are the disk used as raw devices by a database?

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 14:24:44 GMT

excuse the inconvenience
1) discs "unused" are dating?
2) I allocate disk "unused" to a VG?

Re: Disk unused

Torsten. — Thu, 14 Jan 2010 14:30:41 GMT

disk dating ???

Re: Disk unused

James R. Ferguson — Thu, 14 Jan 2010 14:34:50 GMT

Hi (again):

> Is there any way to know if the disks "unused" contain data?????

This leads to another question: Do you scrub physical disks when you return them to a free pool? That is, do you erase any LVM metadata if its an LVM disk? [You could use 'dd' or 'pvremove']. If its a raw disk, do you write all zeros or some random pattern with 'dd' to every disk block?

You could write a simple script to write a known "*UNUSED/FREE/AVAILBABLE*" record to a specific disk address to help you in the future.

Once, again, *documentation* is the surest way to know.

I also agree with Torsten --- "unpresent them and wait if someone complains". This is sometimes the "best" way to uncover things long forgotten in complex environments.

Regards!

...JRF...

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 14:35:02 GMT

sorry Data
contains data??

Re: Disk unused

TTr — Thu, 14 Jan 2010 15:44:35 GMT

You can try and vgimport these to a temporary vg to check if they contain any data. But first you must verify they they are not used anywhere else as mentioned so far. (different path, different server, raw volumes)

Re: Disk unused

Eli Daniel — Thu, 14 Jan 2010 17:44:45 GMT

understand,
that was exactly what I was looking