Hi, In fact, the shallow copy possibility (called "cp --reflink=always") in btrfs and other file systems that support it is really interesting. It would be cool in Java 7+ 's Files.copy(Path, Path, CopyOption) could use this with an additional CopyOption - maybe Java 9. The trick here is to clone the file and its inode, but keep the blocks the same (only when one writes to the file, it clones the block). This could speed up tests, especially Solr where some dirs are copied over and over for every test case. :-)
Uwe ----- Uwe Schindler H.-H.-Meier-Allee 63, D-28213 Bremen http://www.thetaphi.de eMail: u...@thetaphi.de > -----Original Message----- > From: Dawid Weiss [mailto:dawid.we...@gmail.com] > Sent: Monday, December 22, 2014 11:43 AM > To: java-user@lucene.apache.org > Subject: Re: BTRFS ? > > Very interesting, have to take a closer look. Thanks Uwe. > > D. > > On Mon, Dec 22, 2014 at 11:39 AM, Uwe Schindler <u...@thetaphi.de> > wrote: > > Hi Dawid, > > > > there are cool things that might be useful just not for Lucene's Java code. > Like ZFS it now has snapshot functionality and you can copy files mostly > without doing I/O (shallow-copy, it uses copy-on-write semantics to do that). > This might be useful for backup purposes. I know we did most of this already > in the index file format, it might just be a good idea to investigate this > e.g. for > the snapshot/backup functionality of Elasticsearch. You can also quickly put > an index on a separate subvolume, so you can manage it separately from > your other filesystems. Those subvolumes are extensible without hassle if > they get too small (you can also overallocate the real available space). You > can also quickly turn subvolumes into RAIDs. > > > > What is also interesting, is a slightly different approach for journaling. > > This > might improve performance for us, not yet tested. > > > > Uwe > > > > ----- > > Uwe Schindler > > H.-H.-Meier-Allee 63, D-28213 Bremen > > http://www.thetaphi.de > > eMail: u...@thetaphi.de > > > > > >> -----Original Message----- > >> From: Dawid Weiss [mailto:dawid.we...@gmail.com] > >> Sent: Monday, December 22, 2014 8:48 AM > >> To: java-user@lucene.apache.org > >> Cc: Uwe Schindler > >> Subject: Re: BTRFS ? > >> > >> > I spotted Uwe's comment in JIRA the other day "....BTRFS, which > >> > might also bring some cool things for Lucene.". > >> > >> What cool things about BTRFS are you talking about, Uwe? Just curious. > >> > >> Dawid > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > >> For additional commands, e-mail: java-user-h...@lucene.apache.org > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > > For additional commands, e-mail: java-user-h...@lucene.apache.org > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
