FUJITSU CentricStor V3.1D - Manual (Page 40)

40 U41117-J-Z125-7-76
Procedures CentricStor - Virtual Tape Library
Depending on whether the logical volume is still in the RAID system or is only on
a physical volume, the following two situations arise:
Case 1: The volume is migrated to tape and is no longer located in the RAID system.
a) The VLM issues a request to the PLM to read the logical volume LV0005
into the RAID system.
b) The PLM checks its data maintenance to determine the physical volume
on which the requested logical volume LV0005 is located: PV0002.
c) The PLM requests the robot to mount the real tape cartridge PV0002
onto a free tape drive.
d) The data of the logical volume LV0005 is loaded from the tape drive into
the RAID system.
e) A flag is set in the VLM data maintenance to indicate that the logical
volume LV0005 is in the RAID system.
f) Only at this point does the VLM grant the host access to the volume
(mount acknowledged).
Case 2: The volume is present in the RAID system.
The VLM immediately grants the host access to the volume.
3. The host performs read and write accesses on the logical volume.
4. The host issues an unmount job.
In contrast to a real archive system, the job will be confirmed immediately.
5. The VLM checks whether the logical volume in the RAID system has been modified.
Case 1: The logical volume has not been modified.
No further action is taken, since the copy of the logical volume on the
physical volume is still valid.
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