Glossary of OpenClovis Checkpoint Service Terms. More...

Glossary of OpenClovis Checkpoint Service Terms.

Checkpoint

A checkpoint is an entity used by applications to store their states and related information, so that the same can be retrieved in a failover, switchover, or restart scenario.

Dataset

Each checkpoint is structured as datasets in File/Library-based Checkpointing. A dataset is a part of checkpoint, that can be modified or read independently from other datasets. It is similar to sections, used in Server-based Checkpointing.

Serializer

A user-defined function that is called to pack the user-data before it is stored in the persistent memory.

Deserializer

A user-defined function that unpacks the stored data. It is invoked when data is read from persistent memory.

Element

Elements are data of similar types stored within a dataset.

Sections

Each checkpoint is structured as sections in Server-based Checkpointing. A section is a part of a checkpoint, that can be modified/read independently from other sections.

Synchronous checkpoint

When a checkpoint is created with synchronous update option (Synchronous checkpoint), all the writes and checkpoint management calls return only after the checkpoint replicas are updated.

Asynchronous checkpoint

When a checkpoint is created with asynchronous update option (Asynchronous checkpoint), all the writes and checkpoint management calls return after the active replicas of the checkpoint are updated. Other replicas are updated asynchronously.

Asynchronous non-collocated checkpoint

The type of an asynchronous checkpoint, where the active replica is selected by CPS.

Asynchronous collocated checkpoint

The type of an asynchronous checkpoint, where the active replica is selected by the user.

Replica/Checkpoint replica

A copy of the data that is stored in a checkpoint.

Active replica

The replica that is updated first or read from an asynchronous checkpoint. There can be a maximum of one active replica at any given time.

Local replica

A replica located on the node where the checkpoint is opened.

Synchronization

The process of synchronizing the data of a checkpoint across all replicas.

Retention duration

Duration for which a checkpoint is retained after the users have closed it (or users are not using it).

Section expiry time

Duration after which the section is deleted and becomes unuseable.

Default section

If the maximum sections specified by the user is equal to 1, when the checkpoint is created, CPS provides this section by default. The expiry time of this default section is infinite.

Section identifier

The identifier of the section that is unique within a checkpoint.

Section iteration

The process of iterating through all the sections of a checkpoint, to find sections that match a criteria specified by the user.