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HDFS, mail # dev - Re: collision in the naming of '.snapshot' directory between hdfs snapshot and hbase snapshot

Ted Yu 2013-04-16, 17:00
lars hofhansl 2013-04-16, 17:12
Ted Yu 2013-04-16, 21:02
Harsh J 2013-04-17, 08:10
Azuryy Yu 2013-04-17, 08:19
Andrew Purtell 2013-04-17, 16:14
Tsz Wo Sze 2013-04-18, 20:50
Ted Yu 2013-04-16, 02:13
lars hofhansl 2013-04-16, 03:00
Ted Yu 2013-04-16, 03:12
Ted Yu 2013-04-16, 03:18
Azuryy Yu 2013-04-16, 03:23
Ted Yu 2013-04-16, 03:26
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Re: collision in the naming of '.snapshot' directory between hdfs snapshot and hbase snapshot
Tsz Wo Sze 2013-04-16, 02:34
Hi Ted,

It would be great that if Hbase could use a different name since, as you mentioned, ".sanpshot" is user visible in HDFS.  It is used for specifying snapshot paths.  For example, the path /foo/.snapshot/s0/bar is used for accessing /foo/bar in snapshot s0 of /foo.  Thanks.

Sent: Monday, April 15, 2013 7:13 PM
Subject: collision in the naming of '.snapshot' directory between hdfs snapshot and hbase snapshot

This afternoon Huned ad I discovered an issue while playing with HBase
Snapshots on top of Hadoop's Snapshot branch (

HDFS (built from HDFS-2802 branch) doesn't allow paths with .snapshot as a
component while HBase tries to create paths with .snapshot as a component.
This leads to issues in HBase, and one of HDFS or HBase needs to give up
the .snapshot reserved keyword. HBase released Snapshots feature in 0.94.6
(quite recently) and it may not be too late to change HBase to use a
different path component in an upcoming new release.

In HBase these path names are not user visible. If there is a deployment of
0.94.6, one could provide a migration tool that renames .snapshot to
.hbase-snapshot or something to be able to move to the Snapshot release of
Hadoop. On the other hand, .snapshot in HDFS is a user visible name and is
a convention that is used by many file systems. It's a matter of
familiarity with such path names that would help users in using HDFS

I am including the hdfs-dev in this email. Would appreciate if we could
work together and come up with a solution.

You can find sample output from hdfs command here:

Azuryy Yu 2013-04-16, 02:33
lars hofhansl 2013-04-16, 03:47
Ted Yu 2013-04-16, 03:31
Enis Söztutar 2013-04-16, 03:52
Ted Yu 2013-04-16, 04:00
Ted Yu 2013-04-16, 04:17
Ted Yu 2013-04-16, 06:11
Harsh J 2013-04-18, 06:16