Yep, it can be: http://kernelnewbies.org/Ext4#head-3891522e0601162aab24c73c1f148a1e28c6a9d4
On Mon, Mar 12, 2012 at 11:13 PM, Ted Yu <[email protected]> wrote: > Is it possible to upgrade ext4 without losing existing data ? > > Thanks > > On Fri, Nov 11, 2011 at 2:24 PM, Edward Capriolo <[email protected]>wrote: > >> On Fri, Nov 11, 2011 at 4:42 PM, Otis Gospodnetic < >> [email protected]> wrote: >> >> > Hello, >> > >> > I was wondering if anyone has done an experiment with HBase or HDFS/MR >> > where machines in the cluster have heterogeneous underlying file systems? >> > e.g., >> > * 10 nodes with xfs >> > * 10 nodes with ext3 >> > * 10 nodes with ext4 >> > >> > The goal being comparing performance of MapReduce jobs reading from and >> > writing to HBase (or just HDFS). >> > >> > >> > And does anyone have any reason to believe doing the above would be super >> > risky and cause data loss? >> > >> > Thanks, >> > Otis >> > ---- >> > Sematext :: http://sematext.com/ :: Solr - Lucene - Nutch >> > Lucene ecosystem search :: http://search-lucene.com/ >> >> >> Since Hadoop abstracts you from the filesystem guts the underlying file >> system chosen can be mixed and matched. you can even mix and match the >> disks on a single machine. >> >> I have found that ext3 performance gets noticeably poor as disks gets full. >> I captured system vitals from a before and after ext3 to ext4 upgrade. >> >> >> http://www.edwardcapriolo.com/roller/edwardcapriolo/entry/a_great_reason_to_use >> >> Also if you want to get the most out of your disks read this: >> >> >> http://allthingshadoop.com/2011/05/20/faster-datanodes-with-less-wait-io-using-df-instead-of-du/ >> >> XFS should is usually described as on par or slightly better then ext4. >> However anecdotally most hardcore sysadmins I know can account for one XFS >> "i lost my super block" stories :) >> -- Harsh J
