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From "Enis Soztutar (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-7912) HBase Backup/Restore Based on HBase Snapshot
Date Tue, 05 Apr 2016 00:35:26 GMT

    [ https://issues.apache.org/jira/browse/HBASE-7912?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15225385#comment-15225385
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Enis Soztutar commented on HBASE-7912:
--------------------------------------

bq. Lars, "it is as it is" means that it was initial design decision of IBM team and they
have implemented this layout. It is done. To change this layout we need really strong arguments
against it.
Isn't the justification above enough? We should have consistency in the file layout, no matter
it is root directory, exported snapshots or backups. Even between backup types, full and increment
have different layout making it a maintenance burden for no reason. Plus there are even more
things to consider: 
 - For incremental backups, lacking the extra directory level for ServerName means that every
WAL in the backup will end up in the same directory. For 1000 servers, where every servers
rolls the WAL every half an hour, that is 48K WAL files per day. If you have incremental backup
every week, it is 336K files under one directory. We already know that the NN will fail with
this. 
- In the full backup layout, we are repeating the ns + table for no good reason at all. 


> HBase Backup/Restore Based on HBase Snapshot
> --------------------------------------------
>
>                 Key: HBASE-7912
>                 URL: https://issues.apache.org/jira/browse/HBASE-7912
>             Project: HBase
>          Issue Type: Sub-task
>            Reporter: Richard Ding
>            Assignee: Vladimir Rodionov
>              Labels: backup
>             Fix For: 2.0.0
>
>         Attachments: HBaseBackupRestore-Jira-7912-DesignDoc-v1.pdf, HBaseBackupRestore-Jira-7912-DesignDoc-v2.pdf,
HBaseBackupRestore-Jira-7912-v4.pdf, HBaseBackupRestore-Jira-7912-v5 .pdf, HBaseBackupRestore-Jira-7912-v6.pdf,
HBaseBackupandRestore.pdf, HBase_BackupRestore-Jira-7912-CLI-v1.pdf
>
>
> Finally, we completed the implementation of our backup/restore solution, and would like
to share with community through this jira. 
> We are leveraging existing hbase snapshot feature, and provide a general solution to
common users. Our full backup is using snapshot to capture metadata locally and using exportsnapshot
to move data to another cluster; the incremental backup is using offline-WALplayer to backup
HLogs; we also leverage global distribution rolllog and flush to improve performance; other
added-on values such as convert, merge, progress report, and CLI commands. So that a common
user can backup hbase data without in-depth knowledge of hbase.  Our solution also contains
some usability features for enterprise users. 
> The detail design document and CLI command will be attached in this jira. We plan to
use 10~12 subtasks to share each of the following features, and document the detail implement
in the subtasks: 
> * *Full Backup* : provide local and remote back/restore for a list of tables
> * *offline-WALPlayer* to convert HLog to HFiles offline (for incremental backup)
> * *distributed* Logroll and distributed flush 
> * Backup *Manifest* and history
> * *Incremental* backup: to build on top of full backup as daily/weekly backup 
> * *Convert*  incremental backup WAL files into hfiles
> * *Merge* several backup images into one(like merge weekly into monthly)
> * *add and remove* table to and from Backup image
> * *Cancel* a backup process
> * backup progress *status*
> * full backup based on *existing snapshot*
> *-------------------------------------------------------------------------------------------------------------*
> *Below is the original description, to keep here as the history for the design and discussion
back in 2013*
> There have been attempts in the past to come up with a viable HBase backup/restore solution
(e.g., HBASE-4618).  Recently, there are many advancements and new features in HBase, for
example, FileLink, Snapshot, and Distributed Barrier Procedure. This is a proposal for a backup/restore
solution that utilizes these new features to achieve better performance and consistency. 
>  
> A common practice of backup and restore in database is to first take full baseline backup,
and then periodically take incremental backup that capture the changes since the full baseline
backup. HBase cluster can store massive amount data.  Combination of full backups with incremental
backups has tremendous benefit for HBase as well.  The following is a typical scenario for
full and incremental backup.
> # The user takes a full backup of a table or a set of tables in HBase. 
> # The user schedules periodical incremental backups to capture the changes from the full
backup, or from last incremental backup.
> # The user needs to restore table data to a past point of time.
> # The full backup is restored to the table(s) or to different table name(s).  Then the
incremental backups that are up to the desired point in time are applied on top of the full
backup. 
> We would support the following key features and capabilities.
> * Full backup uses HBase snapshot to capture HFiles.
> * Use HBase WALs to capture incremental changes, but we use bulk load of HFiles for fast
incremental restore.
> * Support single table or a set of tables, and column family level backup and restore.
> * Restore to different table names.
> * Support adding additional tables or CF to backup set without interruption of incremental
backup schedule.
> * Support rollup/combining of incremental backups into longer period and bigger incremental
backups.
> * Unified command line interface for all the above.
> The solution will support HBase backup to FileSystem, either on the same cluster or across
clusters.  It has the flexibility to support backup to other devices and servers in the future.
 



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