IBM Z10 EC - Manual (Page 55)

always accepted by some environments. The STP design
provides continuous availability of ETS while maintaining
the special roles of PTS and BTS assigned by the enter-
prise.
The improvement is available when the ETS is confi gured
as an NTP server or an NTP server using PPS.
NTP server on Hardware Management Console (HMC):
Improved security can be obtained by providing NTP
server support on the HMC. If an NTP server (with or with-
out PPS) is confi gured as the ETS device for STP, it needs
to be attached directly to the Support Element (SE) LAN.
The SE LAN is considered by many users to be a private
dedicated LAN to be kept as isolated as possible from the
intranet or Internet.
Since the HMC is normally attached to the SE LAN, pro-
viding an NTP server capability on the HMC addresses
the potential security concerns most users may have for
attaching NTP servers to the SE LAN. The HMC, using
a separate LAN connection, can access an NTP server
available either on the intranet or Internet for its time
source. Note that when using the HMC as the NTP server,
there is no pulse per second capability available. There-
fore, you should not confi gure the ETS to be an NTP server
using PPS.
Enhanced STP recovery when Internal Battery Feature
is in use: Improved availability can be obtained when
power has failed for a single server (PTS/CTS), or when
there is a site power outage in a multisite confi guration
where the PTS/CTS is installed (the site with the BTS is
a different site not affected by the power outage). If an
Internal Battery Feature (IBF) is installed on your System
z server, STP now has the capability of receiving notifi ca-
tion that customer power has failed and that the IBF is
engaged. When STP receives this notifi cation from a server
that has the role of the PTS/CTS, STP can automatically
reassign the role of the CTS to the BTS, thus automating
the recovery action and improving availability.
STP confi guration and time information saved across
Power-on-Resets (POR) or power outages: This
enhancement delivers system management improvements
by saving the STP confi guration across PORs and power
failures for a single server STP-only CTN. Previously, if
there was a POR of the server or the server experienced
a power outage, the time and assignment of the PTS and
CTS roles would have to be reinitialized. You will no longer
need to reinitialize the time or reassign the role of PTS/CTS
across POR or power outage events.
Note: This enhancement is also available on the z990 and
z890 servers, in addition to System z10 and System z9
servers.
Application Programming Interface (API) to automate
STP CTN reconfi guration: The concept of “a pair and
a spare” has been around since the original Sysplex
Couple Data Sets (CDSs). If the primary CDS becomes
unavailable, the backup CDS would take over. Many sites
have had automation routines bring a new backup CDS
online to avoid a single point of failure. This idea is being
extended to STP. With this enhancement, if the PTS fails
and the BTS takes over as CTS, an API is now available
on the HMC so you can automate the reassignment of the
PTS, BTS, and Arbiter roles. This can improve availability
by avoiding a single point of failure after the BTS has taken
over as the CTS.
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