Glossary

This glossary defines the core DFS and Ceph terms used across the Karios DFS guide.

Term	Description	Where You See It
CephFS	POSIX-compatible distributed file system on top of Ceph using metadata and data pools.	Storage > File System
Pool	Logical storage domain where Ceph stores data objects.	Storage > Pools, Block Storage, Object Storage
OSD	Object Storage Daemon that stores data on a physical disk and serves I/O.	Infrastructure > OSDs
Monitor (MON)	Quorum service that maintains cluster maps and cluster state.	Infrastructure > Monitors
Quorum	Majority of monitors required for healthy cluster control-plane operations.	Infrastructure > Monitors
MDS	Metadata Server for CephFS namespace operations such as open, stat, and readdir.	Storage > File System
Subvolume	Named CephFS sub-directory managed as an isolated unit with quotas and snapshots.	Storage > File System > Subvolumes
NFS Export	NFS share that exposes a CephFS path or RGW bucket to clients.	Storage > NFS Shares
Pseudo Path	NFS mount path clients use to access an export.	Storage > NFS Shares
Squash	NFS root identity mapping policy such as root_squash or no_root_squash.	Storage > NFS Shares
RBD Image	Thin-provisioned block device backed by a Ceph pool.	Block Storage > Block Images
Thin Provisioning	Virtual capacity reservation where physical usage grows only as data is written.	Block Storage > Block Images
Snapshot	Point-in-time state capture of a file system or block image.	Storage > File System, Block Storage > Snapshots
Clone	Linked copy derived from a protected snapshot using copy-on-write.	Block Storage > Snapshots
Flatten	Operation that makes a clone independent by copying parent-referenced blocks.	Block Storage > Image Actions
Namespace (RBD)	Partition inside a pool used to isolate block images by tenant or workload.	Block Storage > Namespaces
Trash (RBD)	Soft-delete hold area for block images before permanent purge.	Block Storage > Trash
RGW (Gateway)	RADOS Gateway daemon that provides S3/Swift-compatible object API endpoints.	Object Storage > Gateway
User (Object Storage)	S3/Swift identity with access key and secret key credentials.	Object Storage > Users
Bucket	Top-level object container owned by a user.	Object Storage > Buckets
CRUSH Map	Placement topology and rules Ceph uses to map data onto OSDs.	Advanced > Storage Topology
CRUSH Rule	Rule that defines placement root, failure domain, and optional device class.	Advanced > Storage Topology
Erasure Code Profile	Redundancy profile defined by plugin and k/m chunk values.	Advanced > Storage Topology
Manager Module	Ceph manager extension that adds optional cluster features.	Advanced > Extensions
Alert Silence	Time-bounded notification suppression for matched alerts during planned maintenance.	Monitoring > Alerts > Silences

Note

Terms and examples in this glossary are reference definitions for this DFS guide. Exact UI values in your environment can vary by deployment and release state.