GCP recommends to have each file system on it's own single disk.
You can save time and get the best performance if you format your
persistent disks with a single file system and no partition tables.
From the standard sysadmin perspective it can be seen as a waste of resources considering that there is a limit to the amount of disks you can attach to an instance, however it is easier to manage backups.
- Instances with shared-core machine types are limited to a maximum of
16 persistent disks.
- For custom machine types or predefined machine types that have a
minimum of 1 vCPU, you can attach up to 128 persistent disks.
- Each persistent disk can be up to 64 TB in size, so there is no need
to manage arrays of disks to create large logical volumes. Each
instance can attach only a limited amount of total persistent disk
space and a limited number of individual persistent disks. Predefined
machine types and custom machine types have the same persistent disk
- Most instances can have up to 128 persistent disks and up to 257 TB
of total persistent disk space attached. Total persistent disk space
for an instance includes the size of the boot disk.
- Shared-core machine types are limited to 16 persistent disks and 3 TB
of total persistent disk space.
If I understand correctly you attached 5 individual disks to your instanced and proceeded to create PV,VG,LV and FS. Finally you took snapshots for each disk almost at the same time
It seems you did not make changes in your disks between the snapshots but I do not recommend this architecture for sensitive applications such as a DB as I would be worried about data consistency. I would not surprise me if you repeat the experiment with a longer time between the snapshots of your disks and experience data consistency issues.
I recommend you to take a look at snapshot best practices and scheduled snapshots