IBM Z10 BC manual Preview - Improved STP System Management with

join the two server CTN. Previously, if both the Preferred Time Server (PTS) and the Backup Time Server (BTS) experienced a simultaneous power outage (site failure), or both experienced a POR, reinitialization of time, and special roles (PTS, BTS, and CTS) was required. With this enhancement, you will no longer need to reinitialize the time or reassign the roles for these events.

Preview - Improved STP System Management with

new z/OS Messaging: This is a new function planned to generate z/OS messages when various hardware events that affect the External Time Sources (ETS) confi gured for an STP-only CTN occur. This may improve problem deter- mination and correction times. Previously, the messages were generated only on the Hardware Management Con- sole (HMC).

The ability to generate z/OS messages will be supported on IBM System z10 and System z9 servers with z/OS 1.11 (with enabling support rolled back to z/OS 1.9) in the second half of 2009.

The following Server Time Protocol (STP) enhancements are available on the z10 EC, z10 BC, z9 EC, and z10 BC. The prerequisites are that you install STP feature and that the latest MCLs are installed for the applicable driver.

NTP client support: This enhancement addresses the requirements of customers who need to provide the same accurate time across heterogeneous platforms in an enter- prise.

The STP design has been enhanced to include support for a Simple Network Time Protocol (SNTP) client on the Support Element. By confi guring an NTP server as the

STP External Time Source (ETS), the time of an STP-only Coordinated Timing Network (CTN) can track to the time provided by the NTP server, and maintain a time accuracy of 100 milliseconds.

Note: NTP client support has been available since October 2007.

Enhanced accuracy to an External Time Source: The time accuracy of an STP-only CTN has been improved by adding the capability to confi gure an NTP server that has a pulse per second (PPS) output signal as the ETS device. This type of ETS device is available worldwide from sev- eral vendors that provide network timing solutions.

STP has been designed to track to the highly stable, accurate PPS signal from the NTP server, and maintain an accuracy of 10 microseconds as measured at the PPS input of the System z server. A number of variables such as accuracy of the NTP server to its time source (GPS, radio signals for example), and cable used to connect the PPS signal will determine the ultimate accuracy of STP to Coordinated Universal Time (UTC).

In comparison, the IBM Sysplex Timer is designed to maintain an accuracy of 100 microseconds when attached to an ETS with a PPS output. If STP is confi gured to use

a dial-out time service or an NTP server without PPS, it is designed to provide a time accuracy of 100 milliseconds to the ETS device.

For this enhancement, the NTP output of the NTP server has to be connected to the Support Element (SE) LAN, and the PPS output of the same NTP server has to be con- nected to the PPS input provided on the External Time Ref- erence (ETR) card of the System z10 or System z9 server.

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