We can simplify this by just changing the snapshot dir name to .hbase_snapshot and publishing instructions about to rename the directory in case anybody used that feature in 0.94.6.
-- Lars ________________________________ From: Jonathan Hsieh <j...@cloudera.com> To: "d...@hbase.apache.org" <d...@hbase.apache.org>; lars hofhansl <la...@apache.org> Cc: "hdfs-dev@hadoop.apache.org" <hdfs-dev@hadoop.apache.org> Sent: Monday, April 15, 2013 8:24 PM Subject: collision in the naming of '.snapshot' directory between hdfs snapshot and hbase snapshot constraints: 1) hbase 0.94.6 is released and .snapshot is hardcoded in there. 2) hdfs snapshots is a Hadoop 2.1 or 3.0 feature. I doubt that it will ever make it to 1.x. This hdfs feature ideally this shouldn't affect current A pache Hbase 0.94.x's. 3) hbase 95/96 may default to Hadoop1 or Hadoop 2. these versions should pick a different table snapshot name to respect fs conventions. proposed actions: 1) let's make the hbase snapshot for a conf variable. (hbase. snapshots.dir) let's change the default for hbase 95+. (maybe .hbase-snapshots). we'll also port this patch to 0.94.x 2) let's publish instructions on how to update the hbase snapshot dir: shutdown hbase, config update, rename dir, restart hbase. 3) I lean towards leaving the current default hbase snapshot dir in 94 since it shouldn't be affected. upgrading hbase to 95/96 will require shutdown and update scripts so it seems like the ideal time to autoforce this default change. Thoughts? On Monday, April 15, 2013, lars hofhansl wrote: > OK. Let's try to fix that quickly, so that I can release HBase 0.94.7. > > -- Lars > > > > ________________________________ > From: Ted Yu <yuzhih...@gmail.com> > To: d...@hbase.apache.org; hdfs-dev@hadoop.apache.org > Sent: Monday, April 15, 2013 7:13 PM > Subject: collision in the naming of '.snapshot' directory between hdfs > snapshot and hbase snapshot > > > Hi, > This afternoon Huned ad I discovered an issue while playing with HBase > Snapshots on top of Hadoop's Snapshot branch ( > http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/). > > 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 > snapshots. > > 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: > http://pastebin.com/bBqR4Fvr > > Cheers -- // Jonathan Hsieh (shay) // Software Engineer, Cloudera // j...@cloudera.com
