IBM Systems Magazine, Mainframe Edition - May/June 2013 - 42

Administrator
Getting the
most from
your systems

z/VM SSI Gains Traction
Single system image
feature delivers greater
flexibility and resilience
By Romney White

ince its introduction in 2011 with z/VM* 6.2, client
adoption of the single system image (SSI) feature has
been growing. By enabling clustering of up to four
z/VM systems and introducing mobility for VMs within a
cluster, SSI has brought new flexibility and resilience to address
some long-standing customer requirements.

S

While often regarded as a monolithic capability, SSI comprises several
distinct technologies that together
present the appearance of a single
system. Figure 1 (page 44) shows the
structure of a typical SSI configuration. Its major components are:
Communication—The foundation is a dedicated network and an
exploiting software infrastructure
that enables communication between
z/VM hypervisors. This mechanism—coupled with multisystem synchronization and well-defined cluster
state management—enables many of
the other SSI capabilities.
Shared user directory—
The z/VM user directory holds
the definitions of all VMs and
their configurations. In an SSI
environment, a single user directory
allows a VM to be known to and
activated on any member in the
cluster. SSI prevents a guest from
being simultaneously active on more
than one member.

42

pg 42-45.indd 2

MAY/JUNE 2 013

Shared spool files—Spool
files are used in z/VM to virtualize
unit record devices—card readers and
punches, printers, etc.—and hold VM
console device log files. Regardless of
which member is hosting a VM, its
spool files are made available to it by
sharing them throughout the cluster.
Minidisk protection—
A minidisk is a contiguous area on a
physical disk that can be associated
with a VM as a virtual disk device.
Minidisks can be shared with other
VMs and access to them is established
based on a set of rules and the nature
of the sharing. For example, access to
a minidisk may be requested as readonly, and the request can be made
conditional upon whether another
VM has read/write access to it. In
the SSI environment, these rules are
enforced across the cluster, ensuring
data integrity is maintained.
Shared networks—In addition
to the private hypervisor communication network, customer Ethernet
networks are used to enable commu-

ibmsystemsmag.com/mainframe

4/16/13 9:15 AM


http://www.ibmsystemsmag.com/mainframe

IBM Systems Magazine, Mainframe Edition - May/June 2013

Table of Contents for the Digital Edition of IBM Systems Magazine, Mainframe Edition - May/June 2013

IBM Systems Magazine, Mainframe Edition - May/June 2013
Table of Contents
Editor's Desk: See Beyond the Silos
IBM Perspective: Keys to Successful Software Development
Dashboard: It's a Smarter World After All; Encouraging Exercise; Facebook Fatigue?
Insider: Reimagining Data Protection Requires Due Diligence and Defense in Depth
Case Study: Financing the Future: BNY Mellon increases workload and cuts costs by investing in a standardized mainframe environment
Feature: Making DevOps Real for System z: Linking development and operations for the continuous delivery of software innovation
Feature: Building a DevOps Pipeline: Automated testing to support application development reaps many rewards
Tech Corner: Software-Defined IT Infrastructure: The Next Chapter in Virtualization Benefits
Administrator: Single System Image Feature Delivers Greater Flexibility and Resilience
Solutions: CA Mainframe Application Tuner; Ivory Hub; Genius Project; CICS JS/Server; CA Workload Automation; QWS3270 Tablet
Advertisers Index
Stop Run: Un-Comfort Zone
Reference Point - Global Events, Education, Resources for Mainframe
Services Blueprint Issue 1 2013
2013 Mainframe Buyer's Guide Index
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Intro
IBM Systems Magazine, Mainframe Edition - May/June 2013 - IBM Systems Magazine, Mainframe Edition - May/June 2013
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Cover2
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 1
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Table of Contents
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 3
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 4
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 5
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Editor's Desk: See Beyond the Silos
IBM Systems Magazine, Mainframe Edition - May/June 2013 - CT1
IBM Systems Magazine, Mainframe Edition - May/June 2013 - CT2
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 7
IBM Systems Magazine, Mainframe Edition - May/June 2013 - IBM Perspective: Keys to Successful Software Development
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 9
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 10
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 11
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Dashboard: It's a Smarter World After All; Encouraging Exercise; Facebook Fatigue?
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 13
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Insider: Reimagining Data Protection Requires Due Diligence and Defense in Depth
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 15
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 16
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 17
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Case Study: Financing the Future: BNY Mellon increases workload and cuts costs by investing in a standardized mainframe environment
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 19
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 20
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 21
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 22
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 23
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 24
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 25
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Feature: Making DevOps Real for System z: Linking development and operations for the continuous delivery of software innovation
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 27
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 28
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 29
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 30
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 31
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Feature: Building a DevOps Pipeline: Automated testing to support application development reaps many rewards
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 33
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 34
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 35
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 36
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 37
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Tech Corner: Software-Defined IT Infrastructure: The Next Chapter in Virtualization Benefits
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 39
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 40
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 41
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Administrator: Single System Image Feature Delivers Greater Flexibility and Resilience
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 43
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 44
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 45
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Solutions: CA Mainframe Application Tuner; Ivory Hub; Genius Project; CICS JS/Server; CA Workload Automation; QWS3270 Tablet
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Advertisers Index
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Stop Run: Un-Comfort Zone
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Cover3
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Cover4
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Reference Point - Global Events, Education, Resources for Mainframe
IBM Systems Magazine, Mainframe Edition - May/June 2013 - RF2
IBM Systems Magazine, Mainframe Edition - May/June 2013 - Services Blueprint Issue 1 2013
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SBCover2
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB1
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB2
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB3
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB4
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB5
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB6
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB7
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB8
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB9
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB10
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB11
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB12
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB13
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB14
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB15
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SB16
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SBCover3
IBM Systems Magazine, Mainframe Edition - May/June 2013 - SBCover4
IBM Systems Magazine, Mainframe Edition - May/June 2013 - 2013 Mainframe Buyer's Guide Index
IBM Systems Magazine, Mainframe Edition - May/June 2013 - BG2
IBM Systems Magazine, Mainframe Edition - May/June 2013 - BG3
http://www.ibmsystemsmagmainframedigital.com/mspcomm/ibmsystemsmag/ibmsystems_mainframe_20200910
http://www.ibmsystemsmagmainframedigital.com/mspcomm/ibmsystemsmag/ibmsystems_mainframe_20200708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20200506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20200304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20200102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/2020mfse
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20191112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20190910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20190708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20190506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20190304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/relevantz_20190102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/2019mfse
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20190102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20181112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20180910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20180708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20180506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20180304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20180102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/2018mfse
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20171112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20170910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20170910_v2
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20170708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20170506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20170304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_sesupp
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20170102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_linuxsupp
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20161112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/MainframeSecurity
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20160910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20160708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20160506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20160304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20160102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20151112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150910_se
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150910
http://www.ibmsystemsmagmainframedigital.com/MFSkills
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150506_supp
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20150102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20141112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20140910_v2
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20140910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20140708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_gt_201405
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/BigData
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20140506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20140304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20140102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20131112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20130910_v2
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20130910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20130708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20130506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20130304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20130102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20121112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/buyersguide2013
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20120910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20120708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20120506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20120304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20120102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/ibmsystems_mainframe_2012bg
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20111112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20110910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20110708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20110506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20110304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20110102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20101112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20100910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20100910_bg
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20100708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20100506
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20100304
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20100102
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20091112
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20090910
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20090708
http://www.ibmsystemsmagmainframedigital.com/nxtbooks/ibmsystemsmag/mainframe_20090506
https://www.nxtbook.com/nxtbooks/ibmsystemsmag/mainframe_20090304
https://www.nxtbookmedia.com