STP zOS Considerations David Whitney October 2006

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STP z/OS Considerations David Whitney
October 2006

• whitneyd_at_us.ibm.com

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Agenda

• Why synchronized time?
• Timing networks and CTNs
• z/OS Timing Modes
• Timing Network and timing mode perspectives
• CLOCK parmlib member
• Display information

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z/OS STP Support

• Included in z/OS V1R7 and V1R8, but it is
  disabled.
• The PTFs for OA13344 enables it.
• V1R9 will be shipped with STP support enabled.

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Why does z/OS care about synchronized time?

• Tod clock values are used to
• Provide correct date and time of day
• Correctly order events within and between systems
• Calculate time intervals
• Provide unique identifiers

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Timing Network types

• None No time synchronization between servers.
• ETR Servers synchronized via direct connections
  to a Sysplex Timer.
• Coordinated Time Networks (CTNs)
• Mixed Servers synchronized via STP and a
  Sysplex Timer working together.
• STP only Servers synchronized via STP only.

New with STP
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CTN IDs

• Made up of an STP portion and an ETR portion
• None null null
• ETR null etrid 15
• Mixed stpid etrid IBM_NET1-15
• STP-only stpid null IBM_NET1
• Set or changed from the STP Configuration panel
  on the HMC

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z/OS synchronization modes

• Local
• Server timing mode Local, ETR, or STP
• ETR
• Server timing mode ETR
• SIMETR
• Server timing mode Local or ETR
• ETR
• Server timing mode ETR
• Stratum 1 server in a Mixed CTN
• STP
• Server timing mode STP
• Stratum 2 or Stratum 3 server in a Mixed CTN
• All servers in the CTN in an STP-only CTN
• SIMETR
• Server timing mode Local, ETR, or STP
• Mixed CTN or STP-only CTN

New with STP
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Important Network and Synchronization Mode
Concepts

• Synchronization mode is often the same for a
  Server and an image running on that Server, but
  it may be different.
• Server synchronization mode may be ETR mode
• Image synchronization mode may be LOCAL mode
• Different Server synchronization modes may exist
  within a CTN.
• Servers synchronized to a 9037 will be in ETR
  mode
• Servers synchronized using STP will be in STP
  mode
• Members of a Sysplex may have different
  synchronization modes
• In a mixed CTN there may be ETR mode and STP mode
  images

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CLOCKxx statements

• OPERATOR PROMPTNOPROMPT
• TIMEZONE W E hh.mm.ss
• ETRMODE YES NO
• ETRZONE YES NO
• SIMETRID nn
• STPMODE YES NO
• Specifies whether z/OS is to use STP timing mode
• STPZONE YES NO
• Specifies whether the system is to get the time
  zone constant from STP
• ETRDELTA ss TIMEDELTA ss
• Where
• nn 0 - 31
• ss 0 - 99 seconds, default 10

New statements for STP
10
CLOCK00 prior to STP

• OPERATOR NOPROMPT
• TIMEZONE W 00.00.00
• ETRMODE YES
• ETRZONE YES
• ETRDELTA 10

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CLOCK00 for STP

• OPERATOR NOPROMPT
• TIMEZONE W 00.00.00
• ETRMODE YES
• ETRZONE YES
• STPMODE YES
• STPZONE YES
• TIMEDELTA 10

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Display ETR command output
SP7A IEA282I 09.27.43 TIMING STATUS
573 SYNCHRONIZATION MODE ETR CPC PORT 0 ?
ACTIVE CPC PORT 1 OPERATIONAL
OPERATIONAL ENABLED
ENABLED ETR NET ID15
ETR NET ID15 ETR PORT03
ETR PORT03 ETR ID09
ETR ID09
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Mixed CTN example

• Sysplex Timers provide timekeeping information
  for Mixed CTN
• Parallel Sysplex members or CFs may exist on any
  of the 4 servers
• z9-109 and z990 synchronized to 9037
• Stratum 1 servers in a Mixed CTN
• z890 synchronized to either z9-109 or z990 via
  STP
• z890 is a Stratum 2 server

CLO links
ETR links
z900
P2
z9-109 Stratum 1
z890 Stratum 2
P1
ICF
Coupling links 100 km (max)
ICF
P3
z990 Stratum 1
P4
ETR/CLO links
Coupling links
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D ETR command Mixed CTN (Image P2 on non-STP
capable server)
SP7A IEA282I 09.27.43 TIMING STATUS
573 SYNCHRONIZATION MODE ETR CPC PORT 0 ?
ACTIVE CPC PORT 1 OPERATIONAL
OPERATIONAL ENABLED
ENABLED ETR NET ID15
ETR NET ID15 ETR PORT03
ETR PORT03 ETR ID09
ETR ID09
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D ETR command Mixed CTN (Images P1, P4 on
Stratum 1 servers)
SP7A IEA282I 09.27.43 TIMING STATUS
573 SYNCHRONIZATION MODE ETR CPC PORT 0 ?
ACTIVE CPC PORT 1 OPERATIONAL
OPERATIONAL ENABLED
ENABLED ETR NET ID15
ETR NET ID15 ETR PORT03
ETR PORT03 ETR ID09
ETR ID09 THIS SERVER IS PART OF TIMING NETWORK
IBM_NET115
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D ETR command Mixed CTN (Image P3 on Stratum 2
server)
SP7A IEA386I 10.35.32 TIMING STATUS
637 SYNCHRONIZATION MODE STP THIS SERVER IS
A STRATUM 2 CTN ID IBM_NET1-15
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STP-only CTN example

• Configuration has to be defined
• Must assign Preferred Time Server (PTS) and
  Current Time Server (CTS)
• Optionally assign Backup Time Server (BTS)
• Strongly recommended for continuous availability
• Optionally assign Arbiter
• Recommended for configurations of 3 or more
  servers/CFs
• Improves recovery
• Not assigned in this example

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D ETR command STP only CTN (Image P1 on CTS)
SP7A IEA386I 10.35.32 TIMING STATUS
637 SYNCHRONIZATION MODE STP THIS SERVER IS
A STRATUM 1 CTN ID IBM_NET1 THE STRATUM 1
NODE ID 002084.D32.IBM.02.00000002069D THIS
STP NETWORK HAS NO SERVER TO ACT AS ARBITER
THIS IS THE PREFERRED TIME SERVER
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D ETR command STP only CTN (Image P2 on BTS)
SP7A IEA386I 10.35.32 TIMING STATUS
637 SYNCHRONIZATION MODE STP THIS SERVER IS
A STRATUM 2 CTN ID IBM_NET1 THE STRATUM 1
NODE ID 002084.D32.IBM.02.00000002069D THIS
IS THE BACKUP TIME SERVER THIS STP NETWORK HAS
NO SERVER TO ACT AS ARBITER NUMBER OF USABLE
TIMING LINKS 4

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D ETR command STP only CTN (Image P3 on Stratum
2)
SP7A IEA386I 10.35.32 TIMING STATUS
637 SYNCHRONIZATION MODE STP THIS SERVER IS
A STRATUM 2 CTN ID IBM_NET1 THE STRATUM 1
NODE ID 002084.D32.IBM.02.00000002069D
NUMBER OF USABLE TIMING LINKS 6
Image P4 display similar with different number of
usable timing links
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STP messages

• There are many IEAxxx and IXCxxx messages which
  report current and changed timing status.
• As an example, the following reports the result
  of a successful migration from a mixed CTN to an
  STP-only CTN.
• IXC438I COORDINATED TIMING INFORMATION HAS BEEN
  UPDATED
• FOR SYSTEM sysname
  
• PREVIOUS CTNID IBM_NET1-15
  
  CURRENT CNTID
  IBM_NET1
  

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References

• z/OS V1R8.0 MVS System Commands, SA22-7627
• z/OS V1R8.0 MVS System Messages, SA22-7631 -
  SA22-7640
• z/OS V1R8.0 MVS Assembler Services Reference, Vol
  2, SA22-7607
• Redbooks
• Server Time Protocol Planning Guide, SG24-7240
• Server Time Protocol Implementation Guide,
  SG24-7241