Mike's explanation as to why Linux LPARs should have only IFLs available
is spot on.....this write-up would be a good candidate for the wiki, I
think.
Have a good one.
On 07/14/2010 10:54 AM, Mike Walter wrote:
General Purpose processors are built to be capable of reaching speed 'x',
but depending on what System z you ordered, may be capped at a lower speed
- and thus priced at a lower price. Think: sub-capacity
This makes upgrades very fast and easy for IBM and customers - after an
upgrade (within that model range) has been agreed to, the CE goes into the
machine room and enters the appropriate mystical incantations and the
processor suddenly runs at the faster, agreed on speed. I don't recall if
any outage is even required. It also means that IBM does not have to
build, test, and maintain so many different chips - just one high-speed
chip per model group that can be knee-capped and upgraded though
micro-code as required.
IFLs always run at the model group's maximum speed 'x'. That's part of
the incentive for new Linux for System z customers, they get the full
speed the chip at a much lower cost than if it were running as a General
Processor, and IFL upgrades come along for "free" when the box is upgraded
while you pay for General Purpose CPU engine upgrades.
If Linux work is included on General Processor CPU, they will consume
General Processor CPU cycles. If that Linux work causes an upgrade of the
General Processor, then some software licenses may require an upgrade fee
related to the General Processor upgrade. If the Linux work is confined
to IFL's, when they need more resources you add another (lower-priced,
but full-speed) IFL, which does not affect General Processor product
licensing charges. It is likely that the IFL engine is already aboard
your present System z, too - just not turned on.
Mike Walter
Hewitt Associates
The opinions expressed herein are mine alone, not my employer's.
"Schuh, Richard"<[email protected]>
Sent by: "The IBM z/VM Operating System"<[email protected]>
07/14/2010 10:38 AM
Please respond to
"The IBM z/VM Operating System"<[email protected]>
To
[email protected]
cc
Subject
Re: question to mixed CP an IFL in one LPAR
Do you not control whether a Linux guest is dispatched on IFLs or regular
CPUs via the directory? If a guest can only run on IFLs and not regular
CPUs because of this, do the license fees increase if a Linux workload is
melded in with a regular workload instead of running it in a separate
LPAR?
When did the IFL become faster than a regular CPU?
Regards,
Richard Schuh
-----Original Message-----
From: The IBM z/VM Operating System
[mailto:[email protected]] On Behalf Of Dave Jones
Sent: Wednesday, July 14, 2010 8:06 AM
To: [email protected]
Subject: Re: question to mixed CP an IFL in one LPAR
Franz, the IBM-er is right, you can mix CP and IFL in a
single LPAR with either z/VM 5.4 or 6.1......if you are
running 6.1, your system must be a z10.
However, even if it is technically possible to mix engines, I
generally recommend that you limit your Linux LPARs to IFLs
only. It guarantees that all work in the LPAR will be
dispatched on the faster IFL engines, and may have financial
implications with respect to software licensing charges.
On 07/14/2010 02:34 AM, Franz Josef Pohlen wrote:
Hello listers,
an IBMer has told me that a mixture of CPs and IFLs in one LPAR are
supported on z10 not only with z/VM 6 but also with zVM
5.4. Is this
correct? I thought that for those environments you must have z/VM 6.
--
Dave Jones
V/Soft
www.vsoft-software.com
Houston, TX
281.578.7544
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