6947ch08.fm Draft Document for Review April 7, 2004 6:15 pm
208 IBM eServer zSeries 990 Technical Guide
servers in the take-over site to restore processing power for mission-critical production
workloads. GDPS automation will:
򐂰Perform the analysis required to determine the scope of the failure; this minimizes
operator intervention and the potential for errors.
򐂰Automate authentication and activation of the reserved CPs.
򐂰Automatically restart the critical applications after reserved CP activation.
򐂰Reduce the outage time to restart critical workloads from several hours to minutes.
8.6 Nondisruptive upgrades
Continuous availability is an increasingly important requirement for most customers, and even
planned outages are no longer acceptable. Although Parallel Sysplex clustering technology is
the best continuous availability solution for z/OS and OS/390 environments, nondisruptive
upgrades within a single server can avoid system outages and are suitable to further
operating system environments.
The z990 servers allow concurrent upgrades, meaning they can dynamically add more
capacity to the server. If operating system images running on the upgraded server need no
disruptive tasks to use the new capacity, the up grade is also nondisruptive. This means that
Power-on Resets (PORs), logical partition deactivations, and IPLs do not have to take place.
If the concurrent upgrade is intended to satisfy an “image upgrade” to a logical partition, the
operating system running in this partition must also have the capability to concurrently
configure more capacity online. z/OS and OS/390 operating systems have this capability.
z/VM can concurrently configure new processors and I/O devices online, but it does not
support dynamic storage reconfiguration.
Linux operating systems do not have the capability of adding more resources concurrently.
However, Linux virtual machines running under z/VM can take advantage of the z/VM
capability to nondisruptively configure more resources online (processors and I/O).

Processors

CPs, IFLs, ICFs, and/or zAAPs processors can be concurrently added to a z990 server if
there are spare PUs available on any installed book. The number of zAAPs cannot exceed
the number of CPs plus unassigned CPs on a z990 server.
Additional book(s) can also be installed concurrently, allowing further processor upgrades.
A processor upgrade cannot be performed when CBU or On/Off CoD is activated.
Important: Dynamic add/delete of a logical partition name allows reserved partition ‘slots’
to be created in an IOCDS in the form of extra logical channel subsystem, Multiple Image
Facility (MIF) image pairs, which can be later assigned a logical partition name for use (or
later removed) via HCD, concurrently.
Important: If the z990 STI Rebalance feature (FC 2400) is selected at server upgrade
configuration time, and effectively results in STI rebalancing, the server upgrade will be
disruptive and this outage must be planned. The z990 STI Rebalance feature may also
change the Physical Channel ID (PCHID) number of ICB-4 links, requiring a corresponding
update on the server’s I/O definition via HCD/HCM.