topic Re: disk mount -question in Operating System - HP-UX

disk mount -question

Eli Daniel — Mon, 25 Jan 2010 16:27:23 GMT

question:
if a disk is shown as unsed has data? or not?

Re: disk mount -question

Steven Schweda — Mon, 25 Jan 2010 16:41:29 GMT

If a disk is shown (somewhere) as "unused",
then it probably means that the (unspecified)
OS is not using it. This tells you
approximately nothing about any data which
may or may not exist on the disk. (Perhaps
exactly nothing.)

Re: disk mount -question

Tingli — Mon, 25 Jan 2010 16:50:09 GMT

It is hard to say. If a disk is labeled as unused but it might be used by the virtual machine of the system. So, you must make sure none of the unused disk are used in the virtual system.

Re: disk mount -question

James R. Ferguson — Mon, 25 Jan 2010 17:31:36 GMT

Hi Eli:

You asked this same question (and received your answer --- in part based on your scoring of the replies!) here:

http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1400267

What hasn't satisfied your question aside from perhaps that you wish there were one definitive way (aside from documentation)?

Regards!

...JRF...

Re: disk mount -question

Eli Daniel — Mon, 25 Jan 2010 17:54:32 GMT

In the System Management Homepage displays the disk unsed.
but in the SAM the disk is not shown.

Re: disk mount -question

Eli Daniel — Mon, 25 Jan 2010 17:57:10 GMT

question
if the disk is added in a unsed VG lose the information? (if available)

Re: disk mount -question

Michael Steele_2 — Mon, 25 Jan 2010 17:58:17 GMT

Hi

I think what you or your manager is confused about is the index and addressing and other metadata stored in the disk header, or LVM header.

When you delete data from a disk you destroy the pointer or address that points to the location of the data on the physical surface of the disk.

Only the pointers or addresses to the data is destroyed. Not the data itself.

Why? Takes to long and there is no delete operation per say. Data is overwritten on its physical surface with NULL characters or ZERO's.

Ever reformatting is not sufficient. Reformattig still does not does not write NULLS or ZERO's to the disk surface. Formatting only defines the physical bounds of the disk.

The point is, once the index or addresses to the data is destroyed, you can't access it in any typical way. You have to load it up in something like a hex editor and read everything character by character.

Re: disk mount -question

Eli Daniel — Mon, 25 Jan 2010 18:04:09 GMT

example: c2t0d5 disk unsed
anex.

like to know if there dating?

---------------- Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
0 1/0/4/1/0/4/0.19.100.0.0.0.5 c0t0d5 FA 7bB active alive 0 0
2 0/0/4/1/0/4/0.20.100.0.0.0.5 c2t0d5 FA 8bB active alive 0 0

******************************************************************************
******************************************************************************
******************************************************************************
SAPL917:/> powermt display
Symmetrix logical device count=13
CLARiiON logical device count=0
Hitachi logical device count=0
Invista logical device count=0
HP xp logical device count=0
Ess logical device count=0
HP HSx logical device count=0
==============================================================================
----- Host Bus Adapters --------- ------ I/O Paths ----- ------ Stats ------
### HW Path Summary Total Dead IO/Sec Q-IOs Errors
==============================================================================
0 1/0/4/1/0/4/0.19.100.0.0 optimal 13 0 - 0 0
2 0/0/4/1/0/4/0.20.100.0.0 optimal 13 0 - 0 0

Re: disk mount -question

Michael Steele_2 — Mon, 25 Jan 2010 18:06:33 GMT

RE: "...In the System Management Homepage displays the disk unsed.
but in the SAM the disk is not shown..."

This is a patching issue with SAM only.

RE: "...if the disk is added in a unsed VG lose the information? (if available) ..."

I'm not sure what your question is here because of the grammer, but I'll try to rephrase it best I can. Are you asking: "...if a disk is unused and added to a vg, will the disk lose all its information?...".

Well, there's too much assumption and guessing on my part here. Your going to have to rewrite this.

Re: disk mount -question

Michael Steele_2 — Mon, 25 Jan 2010 18:10:52 GMT

example: c2t0d5 disk unsed
anex.

And NO, there is no data on it. Stop questionign the operating system. The O/S is not going to make a mistake.

For elabaoration on why, see my previous reply about INDEX's and ADDRESSING.

Re: disk mount -question

Eli Daniel — Mon, 25 Jan 2010 20:43:45 GMT

thanks