This question regards creation of custom encrypted full disk setup - that doesn't seem to be (well / at all) documented on the internet.
Basically: idea is to have a full disk (technically partial) encryption setup, with disk split to custom volumes(partitions), protected by single password, without using key files or external boot partition.
Lets start with single fully available hard disk: Main volume group is created: VG1, spanning over entire disk. On it 2 logical volumes VG1/LV1 & VG1/LV2. VG1/LV1 become our ext4 boot partition. VG1/LV2 become our main encrypted partition -> VG1/LV2_C Until this moment this is standard single partition setup, however instead of creating filesystem on it we create physical volume. On this physical volume we create another volume group: VG1/LV2_C/VG2 Then nested volume group is split further into logical volumes based on custom needs resulting in something along following:
VG1/LV2_C/VG2/LVA:/partitionA #encrypted with LV2_C pass
VG1/LV2_C/VG2/LVB:/partitionB #encrypted with LV2_C pass
VG1/LV2_C/VG2/LVC:/partitionC #encrypted with LV2_C pass
etc. etc... (this would seem to also support external /boot partitions, unencrypted volumes (VG1/LV3:), volumes encrypted with separate passwords (VG1/LV4_C:), key files etc.)
My question is - has anyone have any experience with following setup, are there any security/performance/reliability concerns that caused it to be not mentioned anywhere as an option? Topics that would particularly interest me would be:
could VG2 compromise LV2_C security?
will there be noticeable performance overhead over flat standard encrypted volume?
can nested volume groups lead to data loss (i.e. by messing up with pointers or alike)?
is this setup actually what it claims it is (like in case of virtualization) or VG2 is created alongside VG1 and just mapped over its volume's space (this question actually overlap with earlier topics.
This is not a go/stay question as I will be evaluating it on test setup (seem to be working fine now although was behaving slightly weird during creation) - however any inputs would help a lot. Please feel free to let me know what you think. Thanks.