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For both backup options, the physical adapters connecting to the tape devices are owned by
VIOS. A different type of I/O virtualization is used in each case, but the result is the same: the
tape device is available in IBM i as though it were physically attached to the IBM i LPAR. The
single LTO4 SAS-attached tape drive solution leverages Virtual SCSI, so that the tape device first
becomes available in VIOS and is then assigned to IBM i using IVM. The Fibre Channel-attached
tape library solution uses N_Port ID Virtualization (NPIV), so that a tape drive from the library is
directly mapped to IBM i in the SAN, with VIOS managing the physical Fibre Channel (FC)
adapter in a passthrough method.
The sections below will describe the technical details, support statements and implementation
steps for both backup and restore options. A note on support statements: as of the time of
publication, this document contains the complete supported environments for these two main
save and restore options for IBM i on a Power blade. They remain in effect until the online
master copy of the document is updated at:
http://www.ibm.com/systems/power/hardware/blades/ibmi.html.
Any other I/O adapters,
versions of software or tape models may or may not work and are not supported by IBM.
7.2. Save and restore with a single LTO4 SAS tape drive
7.2.1. Technical overview
VIOS can now virtualize the TS2240 SAS-attached tape drive to IBM i, as VIOS has previously
done with disk, optical and network devices. This functionality allows an administrator to perform
backups to the SAS-attached LTO4 tape directly from IBM i, using native save and restore
commands or BRMS.
As mentioned above, the virtualized tape drive is not physically attached to IBM i. The TS2240 is
attached to a SAS CFFv or CIOv adapter in VIOS through a SAS I/O module in the BladeCenter.
Once the tape drive is recognized by VIOS, it is assigned an
rmtX
device name, using rmt0 for
the first one. The rmtX device is virtualized to IBM i by mapping it to a separate Virtual SCSI
server adapter, which is in turn connected to a Virtual SCSI client adapter in the IBM i partition.
Once available in IBM i, the tape drive is recognized as a 3580 model 004 tape device and is
assigned a TAPxx device description. This TAPxx device can then be used for all types of
backup operations using native IBM i save and restore commands or BRMS. The following
diagram illustrates the save and restore environment for IBM i on Power blade:
