Hi, A question, is 2.x ready for production deployment? Thanks On 13 Nov 2012, at 5:19 PM, Harsh J wrote:
> Hi, > > Why not just use the 2.x releases for HA-NNs? There is quite a wide > delta between 0.20.x and 2.x, especially around the edit log areas > after HDFS-1073. > > In any case, I think your question suits [email protected] > more than the user lists, although I don't quite understand what > you're attempting to do (or point). > > On Tue, Nov 13, 2012 at 2:18 PM, lei liu <[email protected]> wrote: >> I want to implement HA function for hadoop-0.20.2. >> >> When I learn the hadoop-2.0 code, I meet some question like this: >> >> Thera are below code in FSEditLogLoader.loadEditRecords method. >> >> if (op.hasTransactionId()) { >> if (op.getTransactionId() > expectedTxId) { >> MetaRecoveryContext.editLogLoaderPrompt("There appears " + >> "to be a gap in the edit log. We expected txid " + >> expectedTxId + ", but got txid " + >> op.getTransactionId() + ".", recovery, "ignoring missing " >> + >> " transaction IDs"); >> } else if (op.getTransactionId() < expectedTxId) { >> MetaRecoveryContext.editLogLoaderPrompt("There appears " + >> "to be an out-of-order edit in the edit log. We " + >> "expected txid " + expectedTxId + ", but got txid " + >> op.getTransactionId() + ".", recovery, >> "skipping the out-of-order edit"); >> continue; >> } >> } >> >> The method use transaction id to guarantee same transaction log is not >> applied to namespace more than once. >> >> But in hadoop-0.20.2, FSEditLog don't store the transaction id into edits >> log file. So I want to know if StandbyNN apply same transaction log to >> namespace more than once, that will lead to the namespace of StandbyNN is >> corrupt? >> >> Please give me some adviceļ¼Thanks. >> >> >> >> Best Regards >> >> LiuLei > > > > -- > Harsh J
