From 803b62f0b2bee7bc795c4275fdb27131747195d3 Mon Sep 17 00:00:00 2001 From: Josh Elser Date: Mon, 30 Jul 2018 14:46:37 -0400 Subject: [PATCH] HBASE-20977 Avoid using the word "snapshot" when defining HBase Snapshots Signed-off-by: Mike Drob --- src/main/asciidoc/_chapters/ops_mgt.adoc | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/src/main/asciidoc/_chapters/ops_mgt.adoc b/src/main/asciidoc/_chapters/ops_mgt.adoc index 7e7001c714c..f7ae38e5274 100644 --- a/src/main/asciidoc/_chapters/ops_mgt.adoc +++ b/src/main/asciidoc/_chapters/ops_mgt.adoc @@ -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.