The following table summarizes the various attributes of replication (synchronous and asynchronous) and metro.
Table 1. Replication and metro - SummaryThe first column lists various replication attributes and the next three columns describe this attributes for asynchronous replication, synchronous replication, and metro, respectively.
Attribute
Asynchronous Replication
Synchronous Replication
Metro
Supported type
Block and file
Block and file
Block
Storage resources
Volumes, volume groups, thin clones, NAS servers, vVols
Volumes, volume groups, thin clones, NAS servers
Volumes, volume groups
Replication type
Asynchronous
Synchronous
Synchronous
Target RPO
Fixed value 5 min - 24 h
0
0
Host access
Active/Passive. Requires a failover
Active/Passive. Requires a failover or RTO>0
Active/Active ALUA path change
Host protocols
SCSI, NVMe
SCSI, NVMe
SCSI
Block WWN/NQN
Different
Different
Same WWN on both ends
Witness
No
No
Yes
RTT/Distance
Not applicable
5milliseconds
5milliseconds*
Performance impact on host access
Minimal impact depending on sizing and workload
Adds additional latency (mirror round-trip-time)
Adds additional latency (mirror round-trip-time)
Snapshot replication
Replication of block snapshots on source. Does not support snapshot replication for File.
Near identical block snapshots. Does not support snapshot replication for File.
Near identical snapshots
Failover test
Yes (for example, file, using a clone)
Yes (for example, file, using a clone)
Not applicable
Conversion synchronous <-> synchronous
Allowed for block resources. Not supported for file.
Allowed for block resources. Not supported for file.