z/VM: CP Commands and Utilities Reference - z/VM - IBM

Usage Notes
The volid is specified as a 1- to 6-character name. See Usage Note 6.
SUSpend PRImary
SUSpend SECondary
indicates that the duplex pair identified by prdev is to be forced into suspended
duplex state. The specified volume, either PRIMARY or SECONDARY, is
marked as the suspended volume, and the other volume becomes the only
operational volume of the duplex pair. See Usage Note 17.
OFF
indicates that the duplex relationship between the duplex pair specified by prdev
is to be ended.
1. When using the DUPLEX ON command
a. To establish a duplex pair, enter:
DUPlex prdev ON [SECDev] srdev [COpy] [PAce nnn]
or
DUPlex prdev ON [SECDev] srdev NOCopy
Note: If NOCOPY is specified, the volumes must already be identical.
b. To re-establish a suspended duplex pair, enter:
DUPlex prdev ON [SECDev] srdev [COpy] [PAce nnn]
or
DUPlex prdev ON [SECDev] srdev RESynch [PAce nnn]
c. To replace the secondary volume of an existing suspended duplex pair,
enter:
DUPlex prdev ON [SECDev] srdev
[COpy] [PAce nnn] [SECVolid volid]
srdev
is a new secondary volume to be used in establishing a new duplex
pair.
2. This command requires that both the primary and the secondary volumes be in
the CP I/O configuration.
3. Caching must be inactive for simplex devices being established as a duplex
pair or joining an existing suspended duplex pair.
4. When re-establishing a suspended duplex pair, the pair must not have pinned
data.
5. The PACE value is not allowed if NOCOPY is specified.
DUPLEX
6. The volume identification label of the primary volume will be copied onto the
secondary volume during the establishing of a new duplex pair, unless the
NOCOPY option is specified. The SECVOLID option allows the primary and
secondary volumes to have different identification labels after replacing the
secondary volume of an existing duplex pair or ending a duplex pair.
7. Attention: To assure that the secondary is a true copy of the primary when
issuing DUPLEX OFF, the pair must not be pending or suspended and DASD
fast write must be made inactive prior to issuing DUPLEX OFF.
8. The device identified by srdev must have a capacity that is equal to or greater
than the capacity of the device identified by prdev.
9. DUPLEX ON requires that both cache and NVS be available to the subsystem.
Chapter 2. CP Commands 415