> why would you do that rather than use minidisks
Just curious, if XRC is wanted, VM doesn't timestamp I/Os, but linux does? 
If you use dedicates, isn't the data movers happier? 

> like 0x0200 and 0x0300
You can use CDL and specify the volume label;
dasdfmt -p -b 4096 -l LNX012 -dcdl -f /dev/dasdd

and DFDSS and VM are happy. You may need to redo the CPFMTXA to use it as 
a volume to contain minidisk, but mount it on zOS, and use DFDSS to backup 
as a CPVOL.

kickstart does not do the "-l" flag on dasdfmt, or I have not been able to 
find a way for it to do it, so volsers like 0x0200 and 0x0300 are the 
outcome.

Thanks



From:
Scott Rohling <[email protected]>
To:
[email protected]
Date:
03/24/2010 02:39 PM
Subject:
Re: initializing z/Linux disks
Sent by:
The IBM z/VM Operating System <[email protected]>



Terry --  You have to init the DASD when using minidisks- using CPFMTXA to 
put a label on -- and you also want to format cylinder 0 to ensure it's 
seen as a CP volume.   When the zLinux guest does an 'init' -- it is doing 
a format of the whole disk - not just an 'init' and label.   You can 
preformat minidisks in Linux format if you want to avoid the time Linux 
takes to do it at kickstart...  if that's what you're looking for.

I would not recommend using DEDICATE --  why would you do that rather than 
use minidisks?   What you need to be aware of is that if you DEDICATE -- 
Linux will label the DASD -- and that's what you'll see at the z/VM level 
-- and are likely to see duplicate labels.  (to things like 0x0200 and 
0x0300, etc...).    Also - if you dedicate - you can't use things like 
DIRMAINT do manage your dasd and keep things in pools, etc -- you have to 
manage it all yourself.

I'm not sure how DFDSS reacts to Linux formatted volumes, offhand ..   it 
does fine with CPVOL volumes and minidisks.

Anyway - I'm not a fan of dedicate's - as you can tell ;-)

Scott Rohling



On Wed, Mar 24, 2010 at 11:53 AM, Martin, Terry R. (CMS/CTR) (CTR) <
[email protected]> wrote:

Hi
 
I have a question. What I have been doing up to this point for a new 
z/Linux guest build is, not necessarily in this order and does not 
necessarily include all steps but, 
 
Crave out the DASD for the z/Linux guest
 
Init the DASD using CPFMTXA putting a label on the disk
 
Setting up the Directory entry for the new guest, which includes 
specifying the MDISK for all of the DASD for the guest.
 
We back up our z/Linux guests on the z/OS side with DFDSS.
 
My question is since when we Kick Start the new z/Linux guest and it 
initializes the DASD during this process is there any compelling reason 
for me to initialize the DASD up front before the guest is Kick Started 
for the first time basically doing a double INIT?
 
If not I assume then I would replace the MDISK statements in the Directory 
entry with DEDICATE statements for each one of the DISKS. We do not share 
DASD between guests here so what is defined to the guest belongs to that 
guest only. Is there anything to be aware of by changing to DEDICATE 
statements from MDISK statements? 
 
My only concern is with the DFDSS backups that I do on the z/OS for the 
guests. I am not sure if it matters or not to DFDSS whether the pack was 
initialized via CPFMTXA or z/Linux during the kick start process?
 
 
Thank You,
 
Terry Martin
Lockheed Martin - Citic
z/OS and z/VM Performance Tuning and Operating Systems Support
Office - 443 348-2102
Cell - 443 632-4191
 

 



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