Ceph as block storage
Block store is the traditional form of disk data storage where the data is divided into blocks and stored using a file system. Block store is best suited for VM disk volume storage needs, where we store large singular files with higher read and write frequencies. Ceph block storage can be well served as a SAN (storage area network) solution.
One added advantage of Ceph is that it has thin-provisioning enabled, which helps in faster data duplication and efficient storage space utilisation. When a disk stored in Ceph is replicated, it doesn’t occupy any memory for the replicated copy. Ceph uses the COW (copyonwrite) method where the block is replicated and updated only on write, else the block is not replicated.
Amazon’s EBS (Elastic Block Storage) is a popular block storage service used generally for volumes of VM instances.