package protos

Get desktop application:
View/edit binary Protocol Buffers messages

Used in: grpc.ReportChunkServerRequest

• optional ChunkServerLocation location = 1

  Used as the unique identifier for this chunkserver.

• uint32 available_disk_mb = 2

  Amount of disk in megabytes available on the server

• repeated string stored_chunk_handles = 3

  The chunk handles for chunks on this server.

Used in: ChunkServer, FileChunkMetadata, grpc.WriteFileChunkReply.ReplicaStatus, grpc.WriteFileChunkRequest

• string server_hostname = 1

  The hostname of this chunk server location

• uint32 server_port = 2

  The port that this chunk server is listening on for requests

The file chunk. Used for serializing/deserializing the data to/from binary for disk storage.

• uint32 version = 1

  The version of the chunk.

• bytes data = 2

  The actual data for the chunk.

Metadata of a given file chunk

Used in: grpc.OpenFileReply, grpc.ReportChunkServerRequest

• string chunk_handle = 1

  An immutable and globally unique UUID chunk identifier. This is assigned by the master at the time of chunk creation.

• uint32 version = 2

  A version number associated with each chunk to distinguish between up-to-date and stale replica. Most update-to-date chunk version known to master for this file chunk. The client, or another chunkserver, should always verify the chunk version number before performing file operations at any chunk location, so that it can always read/write the most up-to-date data. For newly created file chunks, chunk version is always 1.

• optional ChunkServerLocation primary_location = 3

  The primary chunk server selected for a given chunk. The primary dicates mutation order among replicas and other replicas follo. If open request is for file mutation (i.e. write and append mode), this is the chunkserver location for the primary replica; otherwise, it is NULL. Client should send write requests to the primary chunkserver, so it can determine the serialization order of all mutations applied to the chunk, and forward the mutation order to all secondary replicas; The client should check with master again, if the primary no longer holds a lease for write mutations. (Ref: GFS paper section 3.1)

• repeated ChunkServerLocation locations = 4

  A list of chunk server locations indicating where the replica are that are holding this chunk. The client caches the returned location information so that it can directly communicates with chunk servers (within a time frame before cache expires)

Metadata of a given file. The reason that we define the file metadata in proto is that later we will use the protobuf to serialize / deserialize this data to checkpoint / log files

• string filename = 1

  File name

• map<uint32, string> chunk_handles = 2

  An map of chunk index to chunk handle