IBM Storwize V7000, Введение и руководство по внедрению

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Chapter 9. IBM Flex System V7000 Storage Node Copy Services
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FlashCopy mapping states
At any point in time, a mapping is in one of the following states:
򐂰 Idle or copied:
The source and target volumes act as independent volumes even if a mapping exists
between the two. Read and write caching is enabled for both the source and the
target volumes.
If the mapping is incremental and the background copy is complete, the mapping only
records the differences between the source and target volumes. If the connection to both
nodes in IBM Flex System V7000 Storage Node that the mapping is assigned to is lost,
the source and target volumes go offline.
򐂰 Copying:
The copy is in progress. Read and write caching is enabled on the source and the target
volumes.
򐂰 Prepared:
The mapping is ready to start. The target volume is online, but is not accessible. The
target volume cannot perform read or write caching. Read and write caching is failed by
the SCSI front end as a hardware error. If the mapping is incremental and a previous
mapping has completed, the mapping only records the differences between the source
and target volumes. If the connection to both nodes in IBM Flex System V7000 Storage
Node that the mapping is assigned to is lost, the source and target volumes go offline.
򐂰 Preparing:
The target volume is online, but not accessible. The target volume cannot perform read or
write caching. Read and write caching is failed by the SCSI front end as a hardware error.
Any changed write data for the source volume is flushed from the cache. Any read or write
data for the target volume is discarded from the cache. If the mapping is incremental and a
previous mapping has completed, the mapping records only the differences between the
source and target volumes. If the connection to both nodes in IBM Flex System V7000
Storage Node that the mapping is assigned to is lost, the source and target volumes
go offline.
򐂰 Stopped:
The mapping is stopped because either you issued a stop command or an I/O error
occurred. The target volume is offline and its data is lost. To access the target volume, you
must restart or delete the mapping. The source volume is accessible and the read and
write cache is enabled. If the mapping is incremental, the mapping is recording write
operations to the source volume. If the connection to both nodes in IBM Flex System
V7000 Storage Node that the mapping is assigned to is lost, the source and target
volumes go offline.
򐂰 Stopping:
The mapping is in the process of copying data to another mapping. If the background copy
process is complete, the target volume is online while the stopping copy process
completes. If the background copy process is not complete, data is discarded from the
target volume cache. The target volume is offline while the stopping copy process runs.
The source volume is accessible for I/O operations.
򐂰 Suspended:
The mapping started, but it did not complete. Access to the metadata is lost, which causes
both the source and target volume to go offline. When access to the metadata is restored,
the mapping returns to the copying or stopping state and the source and target volumes
return online. The background copy process resumes.