Thanks Enis and Andrew; I think I missed the key point of conformance with other FSes' behavior.
On Wed, Apr 17, 2013 at 11:29 PM, Enis Söztutar <enis....@gmail.com> wrote: > Harsh, the discussion above includes the reasoning behind forcing the > change in hbase rather than hdfs. Although HBase has shipped with this, > HDFS's snapshots are user visible, meaning that you can do: > > hadoop fs -ls /user/foo/.snapshot/ > > Plus, it is a convention for file systems (netapp, etc) to expose snapshots > this way, having a name ".snapshot". HBase's snapshot directories are not > user visible, and not widely used yet. > > Enis > > > On Wed, Apr 17, 2013 at 9:14 AM, Andrew Purtell <apurt...@apache.org> wrote: > >> Thanks for the consideration but we've just committed a change to address >> this as HBASE-8352 >> >> >> On Wednesday, April 17, 2013, Harsh J wrote: >> >> > Pardon my late inquisition here but since HBase already shipped out >> > with a name .snapshots/, why do we force them to change it, and not >> > rename HDFS' snapshots to use .hdfs-snapshots, given that HDFS >> > Snapshots has not been released for any users yet. The way I see it, >> > that'd be much more easier to do than making a workaround for a done >> > deal on HBase, which already has its snapshot's users. >> > >> > @Tsz-Wo - If the snapshots in HDFS aren't a 'generic' feature >> > applicable to other FileSystem interface implementations as well, then >> > .hdfs-snapshots should be fine for it - no? >> > >> > On Wed, Apr 17, 2013 at 2:32 AM, Ted Yu <yuzhih...@gmail.com> wrote: >> > > Hi, >> > > Please take a look at patch v5 attached to HBASE-8352. >> > > >> > > It would be nice to resolve this blocker today so that 0.94.7 RC can be >> > cut. >> > > >> > > Thanks >> > > >> > > On Tue, Apr 16, 2013 at 10:12 AM, lars hofhansl <la...@apache.org> >> > wrote: >> > > >> > >> Please see my last comment on the jira. We can make this work without >> > >> breaking users who are using HDFS snapshots. >> > >> >> > >> ------------------------------ >> > >> *From:* Ted Yu <yuzhih...@gmail.com> >> > >> *To:* d...@hbase.apache.org >> > >> *Cc:* hdfs-dev@hadoop.apache.org; lars hofhansl <la...@apache.org> >> > >> *Sent:* Tuesday, April 16, 2013 10:00 AM >> > >> *Subject:* Re: collision in the naming of '.snapshot' directory >> between >> > >> hdfs snapshot and hbase snapshot >> > >> >> > >> Let's get proper release notes for HBASE-8352 . >> > >> >> > >> Either Lars or I can send out notification to user mailing list so >> that >> > >> there is enough preparation for this change. >> > >> >> > >> Cheers >> > >> >> > >> On Tue, Apr 16, 2013 at 8:46 AM, Jonathan Hsieh <j...@cloudera.com> >> > wrote: >> > >> >> > >> I was away from keyboard when I asserted that hdfs snapshot was a >> hadoop >> > >> 2.1 or 3.0 feature. Apparently it is targeted as a hadoop 2.0.5 >> > feature. >> > >> (I'm a little surprised -- expected this to be a hadoop2 compat >> > breaking >> > >> feature) -- so I agree that this is a bit more urgent. >> > >> >> > >> Anyway, I agree that the fs .snapshot naming convention is long >> standing >> > >> and should win. >> > >> >> > >> My concern is with breaking compatibility in 0.94 again -- if we don't >> > go >> > >> down the conf variable route, I consider having docs to properly >> > document >> > >> how to do the upgrade and caveats of doing the upgrade in the >> > docs/release >> > >> notes blocker to hbase 0.94.7. (specifically mentioning from 0.94.6 >> to >> > >> 0.94.7, and to possibly to 0.95). >> > >> >> > >> Jon. >> > >> >> > >> On Mon, Apr 15, 2013 at 9:00 PM, Ted Yu <yuzhih...@gmail.com> wrote: >> > >> >> > >> > bq. Alternatively, we can detect the underlying Hadoop version, and >> > use >> > >> > either .snapshot or .hbase_snapshot in 0.94 depending on h1 & h2. >> > >> > >> > >> > I think this would introduce more confusion, especially for >> > operations. >> > >> > >> > >> > Cheers >> > >> > >> > >> > On Mon, Apr 15, 2013 at 8:52 PM, Enis Söztutar <enis....@gmail.com> >> > >> wrote: >> > >> > >> > >> > > Because HDFS exposes the snapshots so that the normal file system >> > >> > > operations are mapped inside snapshot dirs, I think HDFS reserving >> > the >> > >> > > .snapshot name makes sense. OTOH, nothing is specific about the >> dir >> > >> name >> > >> > > that is chosen by HBase. >> > >> > > >> > >> > > I would prefer to change the dir name in 0.94 as well, since 0.94 >> is >> > >> also >> > >> > > being run on top of hadoop 2. Alternatively, we can detect the >> > >> underlying >> > >> > > Hadoop version, and use either .snapshot or .hbase_snapshot in >> 0.94 >> > >> > > depending on h1 & h2. >> > >> > > >> > >> > > Enis >> > >> > > >> > >> > > >> > >> > > On Mon, Apr 15, 2013 at 8:31 PM, Ted Yu <yuzhih...@gmail.com> >> > wrote: >> > >> > > >> > >> > > > bq. let's make the hbase snapshot for a conf variable. >> > >> > > > >> > >> > > > Once we decide on the new name of snapshot directory, we should >> > still >> > >> > use >> > >> > > > hardcoded value. This aligns with current code base: >> > >> > > > See this snippet from HConstants: >> > >-- >> > Harsh J >> > >> >> >> -- >> Best regards, >> >> - Andy >> >> Problems worthy of attack prove their worth by hitting back. - Piet Hein >> (via Tom White) >> -- Harsh J
