S3 is object storage — durable, effectively infinite, and accessed over an HTTP API. It is the default place to put blobs in AWS: images, backups, logs, static assets, anything. The core pieces Piece What it is Bucket The top-level container for objects. Its name is globally unique, and it lives in one region. Object A blob plus metadata, addressed by a key. The thing you actually store. Key The object’s “path” — e....
Once an EC2 instance is running, it needs somewhere to put data. AWS gives you three kinds of disk to attach to a VM, and each one behaves very differently. The options Type Storage Lifecycle Scope EBS Block, network-attached Persistent One AZ Instance Store Block, physically on the host Ephemeral — lost on stop/terminate One host EFS File (NFS), network share Persistent Multi-AZ Mental model EC2 ──attaches──> EBS volume (its own dedicated disk, persistent) EC2 ──has──────> Instance Store (host's physical NVMe, ephemeral) EC2 ──mounts───> EFS (network file share, many EC2s share it) In plain terms:...
Snapshots in Apache CloudStack can exist at two levels — VM snapshots and volume snapshots — each serving different purposes and stored in different locations. VM Snapshots A VM snapshot is a hypervisor-level checkpoint of an entire virtual machine. It captures the VM’s disk state and optionally its memory, allowing fast rollback to a previous state. Key points: Stored on primary storage. Created quickly without full data copy. Can include memory state for live restore....
When CloudStack deploys a VM from a template, it uses a linked clone instead of creating a full copy of the disk. This approach saves both time and storage space. What Is a Linked Clone A linked clone is a virtual disk that shares the same base image as another VM or template. It doesn’t duplicate the full data. Instead: The base disk (template) is read-only. The linked clone stores only changes (writes made by the VM)....
Primary storage in CloudStack holds the root volumes of running virtual machines and data volumes attached to them. It operates at the cluster level — all hosts within a cluster share access to the same primary storage pool. Local Storage Each hypervisor uses its own local disk for VM volumes. There is no shared storage between hosts. Characteristics No need for expensive centralized SAN/NAS. Limited functionality — no live migration or HA....