Do you have data stored in HBase that you cannot recreate? HADOOP-2478 will introduce an incompatible change in how HBase lays out files in HDFS so that should the root or meta tables be corrupted, it will be possible to reconstruct them from information in the file system alone.
The problem is in building a migration utility. Anything that we could build to migrate from the current file structure to the new file structure would require that the root an meta regions be absolutely correct. If they are not, the migration would fail, because there is not enough information on disk currently to rebuild the root and meta regions. Is it acceptable for this change to be made without the provision of an upgrade utility? If not, are you willing to accept the risk that the upgrade may fail if you have corruption in your root or meta regions? After HADOOP-2478, we will be able to build a fault tolerant upgrade utility, should HBase's file structure change again. Additionally, we will be able to provide the equivalent of fsck for HBase after HADOOP-2478. --- Jim Kellerman, Senior Engineer; Powerset No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.17.13/1207 - Release Date: 1/2/2008 11:29 AM
