Attempting to perform an FLR on a VM with multiple disks succeeds in mounting the system drive, but not the “data” drive(s). The system drive is smaller than 2.2TB, and the “data” drive is larger than 2.2TB. The FLR shows the “data” drive as “mounted”, but the drive cannot be explored in the vRanger GUI. A Full restore of the data drive will succeed.
The “caveat” here is that the “data” drive is larger than 2.2TB. The only partition schema that can provide support for partitions this size or larger is the GPT (GUID Partition Table). GPT is a relatively new partitioning method (as opposed to MBR partitioning). In comparison to MBR, GPT offers support for disk partitions up to 9.4ZB (zettabytes), and support for up to 128 partitions on one physical disk LUN. GPT partitions are appearing with more regularity on the following platforms:
- Intel-based Mac systems (the GPT schema was developed originally by Intel)
- Some flavors of UNIX/Linux
- Some later 64-bit editions of Windows operating systems (there is no 32-bit Windows Support for GPT).
The Full Restore works, since the block-level restore will simply recreate the entire virtual disk (including partition information, etc.) from the ground-up. The FLR engine, however, will attempt to mount the data drive as an MBR-formatted disk (which it’s not), and will be attempting to mount each volume from Logical Block Address (LBA) 0. In GPT, LBA 0 contains a “protective MBR”, which prevents OS versions that don’t recognize GPT from overwriting the GPT partition. Instead, an MBR-only OS, or vRanger’s FLR engine, will see this GPT partition as “Unknown” and with zero free space due to this “feature” of GPT. This is what causes the GPT drive to show as “mounted”, but otherwise be non-functional.
There is no workaround for supporting GPT partitions as FLRs. MBR-formatted disks are the ONLY supported disks via FLR, and hence, a maximum size of an FLR volume is 2.2TB.A future release of vRangerPro DPP may offer support for GPT.
