SnapDrive has a few limitations for provisioning RDM LUNs. You must be aware of the limitations that might affect your environment.
- An RDM LUN cannot serve either as a boot disk or system disk.
- SnapDrive does not support RDM LUNs in Internet Small Computer System Interface (iSCSI) environments.
- SnapDrive does not support MPIO in the guest operating system, although VMware ESX server supports MPIO.
- When the transport protocol is FCP, the igroup that is specified in the CLI command is ignored by SnapDrive, and the igroup is automatically created by the virtual interface.
- You can rename, move, or delete the /usr/bin/rescan-scsi-bus.sh script that is bundled as part of sg3_utils to avoid limiting the number of RDM LUNs to eight.
Note: If you want to retain /usr/bin/rescan-scsi-bus.sh in sg3_utils and avoid limiting the number of RDM LUNs to eight, then you must create a wrapper script /root/dynamic-lun-rescan.sh and from that script run /usr/bin/rescan-scsi-bus.sh, with the
options-w, -c, and -r and assign full permissions.
The following is an example of the modified content of
/root/dynamic-lun-rescan.sh:
#cat /root/dynamic-lun-rescan.sh
#Wrapper script used to call the actual rescan script.
/usr/bin/rescan-scsi-bus.sh -w -c -r
Limitations related to VMware ESX server