Setting the storage protocol
Because the Volume Shadow Copy Service and Virtual Disk Service supports the ISCSI feature for SAN Volume Controller 5.1 or later, the storage protocol setting is determined by the protocol that attached the target LUNs to the host.
The following options are available for this setting:
- Auto
- Volume Shadow Copy Service and Virtual Disk Service automatically chooses the appropriate protocol. If no protocol is available on the host, the snapshot fails.
- FC
- Volume Shadow Copy Service and Virtual Disk Service chooses the Fibre Channel protocol. If the FC protocol is not available, the snapshot fails.
- ISCSI
- Volume Shadow Copy Service and Virtual Disk Service chooses the SCSI protocol. If the ISCSI protocol is not available, the snapshot fails.
Use the following command to set the storage protocol: ibmvcfg set storageprotocol <auto, fc, iscsi>
If more than one storage protocol is installed on the host and
guest OS, Volume Shadow Copy Service and Virtual Disk Service follows
an algorithm to choose the correct protocol. The protocol is as follows:
- Protocol setting is auto
- If FC and ISCSI coexist, choose FC before ISCSI.
- If ISCSI installed on both guest and host, choose ISCSI on guest before on host.
- Protocol setting is FC
- If FC protocol is available, choose uses FC protocol on host.
- Protocol setting is ISCSI
- Ignore FC configuration with this setting.
- If ISCSI is installed on both guest and host, choose ISCSI on guest before on host.
Priorities for storage protocol settings lists the protocol settings and their priorities.
| Protocol Setting | Guest OS | Host | Using |
|---|---|---|---|
| Auto | None ISCSI (software initiator) |
FC, ISCSI | FC on Host |
| FC | FC on Host | ||
| ISCSI | ISCSI on host | ||
| None | ERROR | ||
| FC, ISCSI | FC on Host | ||
| FC | FC on Host | ||
| ISCSI | ISCSI on Guest | ||
| None | ISCSI on Guest | ||
| FC | None | FC, ISCSI | FC on Host |
| FC | FC on Host | ||
| ISCSI | ERROR | ||
| None | ERROR | ||
| ISCSI (software initiator) | FC, ISCSI | FC on Host | |
| FC | FC on Host | ||
| ISCSI | ERROR | ||
| None | ERROR | ||
| ISCSI | None | FC, ISCSI | ISCSI on host |
| FC | ERROR | ||
| ISCSI | ISCSI on host | ||
| None | ERROR | ||
| ISCSI (software initiator) | FC, ISCSI | ISCSI on Guest | |
| FC | ERROR | ||
| ISCSI | ISCSI on Guest | ||
| None | ERROR |