OpenStack Storage (Cinder & Swift) Flashcards

What is Ceph RBD commonly used for in OpenStack deployments?

Answer: As a unified backend for Cinder block, Glance image, and Nova ephemeral storage

Ceph RBD (RADOS Block Device) is widely used as a unified storage backend for Cinder, Glance, and Nova in production OpenStack.

What is the Swift 'ring' responsible for?

Answer: Determining the placement of objects, containers, and accounts across storage nodes

The Swift ring is a data structure that maps partition names to physical storage devices/nodes for data placement.

Which Cinder feature allows a volume to be attached to multiple instances simultaneously (read/write)?

Answer: Multi-attach

Cinder multi-attach allows a single volume to be attached to multiple VM instances at the same time for shared access.

In Swift, what does the term 'consistency' refer to?

Answer: Swift uses eventual consistency where replicas sync asynchronously

Swift uses an eventual consistency model where object replicas may temporarily be out of sync but converge over time.

What is Cinder 'volume type' used for?

Answer: Defining storage characteristics (e.g., SSD, replicated, encrypted) for volume creation

Cinder volume types define storage quality-of-service characteristics like performance tier, replication level, or encryption.

What protocol does Cinder most commonly use to present LVM-backed volumes to compute nodes?

Answer: iSCSI

Cinder's LVM driver presents volumes to compute nodes via iSCSI (Internet Small Computer System Interface) by default.