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VAXcluster Management
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VAXcluster - VMS V3.X
o Components
- CI Star Coupler
- VAX Processors
- HSC-50s with disks
o Shared HSC-50 disk controller
o Management issues
- Avoid unintended sharing of disks
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VAXcluster - VMS V4
o Components
- Distributed lock manager
- VAX processors
- HSC-50s with disks and tapes
- All interconnected with CI
o High degree of sharing
o Management issues
- The cluster IS the system
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Cluster Styles
o Homogeneous nodes
o Heterogeneous nodes
o  ... with respect to
- User environment
- UAF
- Layered products available
- Hardware functions available
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Configurations
o 1 to 16 VAX Processors
- VAX-11/750
- VAX-11/780
- VAX-11/782 (counts as 1)
- VAX-11/785
o 4 Mb or more memory
o Plus 0 to 15 HSC-50s
o Up to 16 VAXes plus HSC-50s
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HSC-50 Disk Support
o RA60, RA80, RA81
o Dual-path with automatic failover
o Volumes accessible to all nodes
o Full Sharing at ALL levels
- Volume
- File
- Record
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Local Disk Support
o Can be accessible to cluster
o Full read-write support of dual-ported MASSbus disks
o DCL commands
  $ SET DEVICE /SERVED DMA0:
  $ SET DEVICE /DUAL_PORT /SERVED DBA0:
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Device Naming
o Unique name for each cluster accessible device
  ALPHA$DUA123   B$DBC3
o All devices respond to name of form:
  local-node-name $ old-device-name
  e.g.  DECUS$TTA0
o This scheme completely covers single access path situations
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Allocation Class Names
o Every device must have a unique name
o Need unique name for multi-path disks
o Controller (HSC-50 or VAX) is member of ALLOCATION CLASS
o Allocation class is number
- 0 : special, assumed unique
- 1 - 255
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Allocation Classes
o All controllers servicing a multi-path disk must have same non-zero allocation class
o Allocation class is used to name devices, e.g. $3$DBB3
o If nodes A and B are in allocation class 7, the following are equivalent:
  A$DUA2, B$DUA2, $7$DUA2
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System Device Options
o Boot from roots on different disks
- One system disk per VAX
o Boot from multiple roots on same disk
- Multiple VAXes per system disk
- No sharing of system files
o Boot from common, shared root
- Multiple VAXes per system disk
- Most system files are shared
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Common System Root
o Each system has minimal system specific root
  [SYS0], etc
o Shared, common root
- Subdirectory of each system specific root
- [SYS0.SYSCOMMON], etc
o SYS$SYSTEM, etc are SEARCH LISTS
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System root searching
o File search order:
- Look in system-specific root
- Look in common root
o Example : SYS$SYSTEM
- First: [SYS0.SYSEXE]
- Then:  [SYS0.SYSCOMMON.SYSEXE]
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System Specific Root Contents
o Swap, Page, Dump files
o SYSGEN parameters (VAXVMSSYS.PAR)
o DECnet node database
o Operator log
o Error log
o Accounting log
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Shared system disk
o Issues
- Very easy to manage
- Layered products
  Install once for cluster
  Must be licensed on all nodes
- Availability
- Performance
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Job Controller
o Batch and device queues are cluster resources
o Load Distribution
- Batch jobs
- Devices (printers, etc)
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DCL commands for Jobctl
  $ START /QUEUE /MANAGER queue-file
  $ INIT := INITIALIZE /QUEUE /START
  $ INIT /BATCH /ON=RED:: RED_BAT
  $ INIT /BATCH SYS$BATCH -  
     /GENERIC=(RED_BAT,BLUE_BAT)
  $ INIT /ON=BLUE::LPA0: SYS$PRINT
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Operator Support
o Mount / dismount a disk on all nodes
o DCL example
  $  MOUNT /CLUSTER RED$DU9: WRK02
  $  DISMOUNT /CLUSTER BLUE$DBA2:
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Operator Terminals
o Receive requests from all nodes
o One operator can service requests from all nodes
o Cluster Broadcast
- REPLY can broadcast messages to all nodes
- DCL example
  $ REPLY /ALL ""Mounting WORK03""
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Cluster status utility
o Interactive utility to display cluster status
o Tailorable Display
o Initialization file
o DCL command
  $ SHOW CLUSTER
o Try it!
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