Here is another possibility.
As in your possibility number 1 write a CMS format on every new disk.
Then run CMS2CDL exec which can be downloaded from IBM's VM download page.
The CMS2CDL runs very quickly, it only writes a CDL VTOC with LINUX
partition information.
CMS2CDL first checks that the disk is CMS format.
DEF T3390 100 100
format 100
z
DMSFOR603R FORMAT will erase all files on disk Z(100). Do you wish to
continue? Enter 1 (YES) or 0 (NO).
1
DMSFOR605R Enter disk
label:
t100
DMSFOR733I Formatting disk
Z
DMSFOR732I 100 cylinders formatted on
Z(100)
Ready; T=0.01/0.02 08:46:36
cms2cdl 100
Ready; T=0.01/0.01 08:47:33
lvtoc 100
Extent information for dasd at 100 volid= 00T100
FROM CYL-HEAD TO CYL-HEAD --- DSN ---
00000 00000 00000 00000 * * * RESERVED * * *
00000 00001 00000 00001 * * * V T O C * * *
00000 00002 00099 00014 LINUX.V00T100.PART0001.NATIVE
Ready; T=0.01/0.01 08:41:15
On Wed, Mar 13, 2013 at 1:59 AM, Pavelka, Tomas <tomas.pave...@ca.com>wrote:
> Thanks for the replies, here are my thoughts on the problem:
>
> I agree that before a minidisk is given to a guest (before the guest is
> started for the first time) the minidisk needs to be formatted and any data
> that was previously on the disk erased. The question is, when to do it and
> from which OS.
> I have the ability to create both the new guest and the minidisk from
> Linux (via SMAPI) but not the ability to safely format the disk from Linux,
> because I cannot safely bring the disk online for format. By unsafe I mean
> that bringing the disk online can create contention on the real device that
> can last several minutes.
>
> There are several possibilities I can think of:
> 1) Format every newly created disk in CMS before formatting in Linux.
> Directory maintenance products can do this. This means every disk would be
> formatted twice and every new disk creation would take twice as long
> (unless you stay with CMS format and not use CDL at all).
> 2) Do a security erase on every deleted disk. Again directory managers can
> do this, but the setting is optional. If you want to do this, you have to
> follow this rigorously on the entire DASD pool on which minidisks are
> created. One deletion without security erase can potentially cause trouble.
> 3) Write nonsense data to the first tracks of the disk so that Linux would
> not recognize it as a known format and would not go into loops when the
> data on the disk is not right. Similar to 1) but faster.
>
> After this, it is safe to format a disk with CDL from Linux.
>
> As Mark has suggested, I need the ability to format the disk from Linux
> without needing to put it online first with Linux examining the contents.
> Without this, the CDL format is incomplete as it can only be safely applied
> to an already formatted disk.
>
> As for the security question about Linux running on LPAR with disk shared
> by z/OS: what makes Linux different from other platforms? If Linux is not
> used to format disks, there must be another OS that has the ability to wipe
> out any of the shared disks and the person doing the format must know which
> disk they are formatting. Also, we are talking about security in the sense
> of preventing accidental deletion. A malicious user having access to Linux
> sharing disks with zOS can do harm to the shared disks by using
> raw_track_access unless the shared disks are protected against access from
> Linux. (As long as the attacker knows CKD architecture. As I have recently
> learned, you cannot just redirect /dev/zero to the disk in raw track format
> ;-))
>
> Tomas
>
> ----------------------------------------------------------------------
> For LINUX-390 subscribe / signoff / archive access instructions,
> send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or
> visit
> http://www.marist.edu/htbin/wlvindex?LINUX-390
> ----------------------------------------------------------------------
> For more information on Linux on System z, visit
> http://wiki.linuxvm.org/
>
----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit
http://www.marist.edu/htbin/wlvindex?LINUX-390
----------------------------------------------------------------------
For more information on Linux on System z, visit
http://wiki.linuxvm.org/
