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HBASE-20977 Avoid using the word "snapshot" when defining HBase Snapshots 

Signed-off-by: Mike Drob <mdrob@apache.org>
This commit is contained in:
Josh Elser 2018-07-30 14:46:37 -04:00
parent c075f33fc7
commit 803b62f0b2
1 changed files with 6 additions and 3 deletions
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src/main/asciidoc/_chapters/ops_mgt.adoc
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@ -2394,9 +2394,12 @@ Since the cluster is up, there is a risk that edits could be missed in the expor
[[ops.snapshots]]
== HBase Snapshots
HBase Snapshots allow you to take a snapshot of a table without too much impact on Region Servers.
Snapshot, Clone and restore operations don't involve data copying.
Also, Exporting the snapshot to another cluster doesn't have impact on the Region Servers.
HBase Snapshots allow you to take a copy of a table (both contents and metadata)with a very small performance impact. A Snapshot is an immutable
collection of table metadata and a list of HFiles that comprised the table at the time the Snapshot was taken. A "clone"
of a snapshot creates a new table from that snapshot, and a "restore" of a snapshot returns the contents of a table to
what it was when the snapshot was created. The "clone" and "restore" operations do not require any data to be copied,
as the underlying HFiles (the files which contain the data for an HBase table) are not modified with either action.
Simiarly, exporting a snapshot to another cluster has little impact on RegionServers of the local cluster.
Prior to version 0.94.6, the only way to backup or to clone a table is to use CopyTable/ExportTable, or to copy all the hfiles in HDFS after disabling the table.
The disadvantages of these methods are that you can degrade region server performance (Copy/Export Table) or you need to disable the table, that means no reads or writes; and this is usually unacceptable.