org.apache.hadoop.hbase.master.snapshot

Class MasterSnapshotVerifier

java.lang.Object

org.apache.hadoop.hbase.master.snapshot.MasterSnapshotVerifier

@InterfaceAudience.Private
 @InterfaceStability.Unstable
public final class MasterSnapshotVerifier
extends Object

General snapshot verification on the master.

This is a light-weight verification mechanism for all the files in a snapshot. It doesn't attempt to verify that the files are exact copies (that would be paramount to taking the snapshot again!), but instead just attempts to ensure that the files match the expected files and are the same length.

Taking an online snapshots can race against other operations and this is an last line of defense. For example, if meta changes between when snapshots are taken not all regions of a table may be present. This can be caused by a region split (daughters present on this scan, but snapshot took parent), or move (snapshots only checks lists of region servers, a move could have caused a region to be skipped or done twice).

Current snapshot files checked:

1. SnapshotDescription is readable
2. Table info is readable
3. Regions

• Matching regions in the snapshot as currently in the table
• RegionInfo matches the current and stored regions
• All referenced hfiles have valid names
• All the hfiles are present (either in .archive directory in the region)
• All recovered.edits files are present (by name) and have the correct file size

Constructor Summary

Constructors

Constructor and Description
MasterSnapshotVerifier(MasterServices services, SnapshotProtos.SnapshotDescription snapshot, org.apache.hadoop.fs.Path rootDir)

Method Summary

Modifier and Type	Method and Description
void	verifySnapshot(org.apache.hadoop.fs.Path snapshotDir, Set<String> snapshotServers) Verify that the snapshot in the directory is a valid snapshot

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MasterSnapshotVerifier

public MasterSnapshotVerifier(MasterServices services,
                              SnapshotProtos.SnapshotDescription snapshot,
                              org.apache.hadoop.fs.Path rootDir)

Parameters:

services - services for the master

snapshot - snapshot to check

rootDir - root directory of the hbase installation.

Method Detail

verifySnapshot

public void verifySnapshot(org.apache.hadoop.fs.Path snapshotDir,
                           Set<String> snapshotServers)
                    throws CorruptedSnapshotException,
                           IOException

Verify that the snapshot in the directory is a valid snapshot

Parameters:

snapshotDir - snapshot directory to check

snapshotServers - ServerName of the servers that are involved in the snapshot

Throws:

CorruptedSnapshotException - if the snapshot is invalid

IOException - if there is an unexpected connection issue to the filesystem