Since your concern is data loss using LVM, it's useful to discuss loss of one of your two disks using the (3) LV configurations available to choose from:
Linear: The DEFAULT option when creating an LV without supplying any switches to create the other two types of LV's below. In a Linear LV, if a Physical Volume (PV) drops out of the Volume Group (VG), you only lose the LV(s) on that PV. However, if an LV spans MULTIPLE PVs and any PV (disk) it uses drops out, the entire LV will be lost. This is logical: the filesystem is spanned across the 2 PVs, so it would be catastrophically damaged with the loss of either disk. Any LV's residing on or NOT spanned across the missing PV member will survive.
Striping: Specify the " -i " switch when creating an LV. Although this provides better write performance, ALL data is written round-robin across the striped PVs. If any PV in the stripe is lost, so too are ALL LVs residing on ALL the PVs.
Mirroring: Specify the " -m " switch when creating your LV. This is analogous to RAID1: Increased fault tolerance to protect against data loss, but uses twice the space.
Finally, when managing data- LVM, RAID or no abstraction at all- you're only as good as your PROVEN backups.
Check How Physical Extents Mapped
To see how your data is mapped in relation to PVs it lives on:
Check if LV's are striped (multiple PVs)
If you have multiple PVs and need to determine if the LV is striped across them:
Simplified Illustrative Example:
As you can see in the illustration, since LV "var" requires extents from all three PVs, were any of the PVs lost, the filesystem on LV "var" would be catastrophically damaged.