WAVV
Requirement Form[Informati1]
Date: 08/29/2006 Requirement #: WAVV200706
Title: Provide emulated ECKD
devices delivered over SCSI drives
Detailed Problem Description: Complete the emulated device
over SCSI/FCP support introduced in z/VM 4.4 and 5.x to include emulation of
ECKD DASD on generic SCSI/FCP disk devices.
Priority:
High Requested Completion
Date: Next Release Requirement
Type: Compatibility/Migration
Business Justification: In many small to medium-sized shops, the amount of money available
to invest in mainframe technology is limited compared to the funding accessible
to the open systems environment. Often, significant disk resources are
duplicated or over-provisioned in the open systems environment, but are not
accessible for reuse in the mainframe environment due to the requirement for
specialized interfaces and separate management to support mainframe-specific
environments. Enabling software emulation of mainframe devices on top of a
generic SCSI/FCP infrastructure would allow System z infrastructure to leverage
these existing enterprise infrastructure investments directly, improving the
TCO argument for maintaining System z-based infrastructure. (It is clearly acknowledged that software emulation
has a performance impact compared to native performance)
Even given the recent price reductions for the System z BC and EC machines, in
some cases, the cost differential to implement separate disk for a System z
environment (or add specialized interfaces to support FICON attachment of an
existing disk array) is such that pricing is a deciding factor to preserve a
System z environment. Similarly,
environmental issues (floor space, power consumption, heat dissipation) may
dictate that additional disk units to support only a single platform argue
against retaining the System z solution as a "difficult to interoperate
with" solution.
Currently, only VSE, Linux and VM fully support FBA DASD. We are aware of work
being done to z/OS to tolerate FBA disk, but until this work is completed, ECKD
disk is required. If IBM is to open up
additional market opportunity for z/OS or other ECKD-only systems in the short
term, ECKD emulation is necessary to open those opportunities.
It is important to note that ECKD emulation on SCSI disk has been done in the
past for the P/390, R/390, and Multiprise systems, and it is clear from a
cursory examination of the z/VM EDEV SCSI stack that these previous attempts
could be used as a starting point to provide this type of emulated function.
As z/OS continues to postpone implementation of FBA DASD, the ability to
support z/OS and other older systems that rely on ECKD DASD relies on the
availability of ECKD disk. This cannot be accomplished without emulation in a
SCSI-only system.
There is also a security advantage in that encryption devices for SCSI devices
are substantially less expensive than replacing existing channel-attached
devices, and can participate in a enterprise-wide key management process that
does not need native OS support.
Impact: Further argument to
remove the mainframe and replace with "more compatible" device.
[Informati1]Please be precise and short. The Benefit section is extremely important – please make a business case.Proofread - recheck accuracy of contact information before saving.File as unique name-WRvviinn, where vv=vendor initials, ii=your initial, ‘nn’ to number each requirement. Ex.: Wribwm01 ib=IBM, wm=wayne merySubmit your labeled diskette (with your full name) to the requirements coordinator, a black shirt WAVV manager, the registration desk or copy it to the root drive of a registration or workroom PC.*