Please, no more internal DASD! Don't even mention it!
I think I have worked with every 360/370/390 that had
internal dasd and every one of them became a disaster.
If not all of them at least a few more than I wanted to!
When it comes time to upgrade the software and/or
hardware we always ran into a brick wall in moving
the system or getting an alternate boot volume.
Way more headaches than it was ever worth.
Please don't give anyone any ideas!
Regards,
Dennis
David Boyes
<dboyes@sinenom To: [EMAIL PROTECTED]
ine.net> cc:
Sent by: Linux Subject: Re: Can z800 attach to Sun SAN
9960 for S/390 Linux?
on 390 Port
<[EMAIL PROTECTED]
ARIST.EDU>
05/20/02 09:21
AM
Please respond
to Linux on 390
Port
> There is no mention in the General Information manual what
> this support of
> for or if there are any restrictions. I am going to guess
> that (almost) any
> SCSI device can then be accessed by Linux for zSeries. I
> would speculate
> that this may be geared for large capacity tape device
> support, so that Linux
> can be used as a network backup server.
In fact, the demonstration at LinuxWorld was a CD-RW being driven by a
Linux
guest as well as a LTO drive.
> On Sunday 19 May 2002 02:02 pm, you wrote:
> > This is confusing....can you expand on your reply...
> > If I still need ECKD for Z/VM,
> > then how does this new feature benefit
> > the Linux environment...since most of us
> > will be running Linux under z/VM??
Consider that you can dedicate devices to guests, and then VM gets out of
the way as much as possible. This allows the guest to do things that VM
doesn't know how to do directly. AFAIK, this is pretty standard process for
new function in the VM world -- the first release of a new technology is
usually guest-only support, then the following release allows VM to use it
natively.
For now, you need enough ECKD disk to store the VM system, the VM
paging/spooling disks, and a few small minidisks for booting your Linux
guests, since the FBA boot support for Linux hasn't been updated in a
while.
The rest of your disk subsystem can be (from the VM perspective) ATTACHed
and/or DEDICATEd to Linux guests directly, and they can do FCP to their
hearts content without VM having to know anything about it. This would
allow
the Linux guests to get at the data.
In time, VM will probably be able to cope with FCP disks directly -- VM and
VSE were the only IBM OSes ever to really understand FBA, and I think that
VM may be the only one left that still does understand booting from FBA
(somebody in VSE-land correct me if I'm wrong). Still, FCP disk is
different
from a 3370, so some of the boot code for VM will need to get rewritten.
This will take time, and given the recent staffing cuts at IBM, I suspect
this may be a while in coming.
This requirement for ECKD disk seems to be one of the flaws in the z800
(along with a lack of an integrated console controller). It seems like
adding some internal disk would be a good improvement; doesn't have to be
high-performance, but enough to IPL the system would be a big plus....
