corrupt tlog causes fullCopy download index files every time reboot a node

There are two questions:
1. The tlog of one replica of shard1 is damaged by some reason. We are still looking for the reason. Please give some clue if you are familia with this problem.

2. The error replica successed to recovery by fullcopy download index files from leader. Then I killed the instance and started it again, the recovery process still is fullcopy download. In my opinion, after the first time fullcopy recovery, the tlog should be fixed. Here is some log:

2013-02-28 15:04:58,622 INFO org.apache.solr.cloud.ZkController:757 - Core needs to recover:metadata
2013-02-28 15:04:58,622 INFO org.apache.solr.update.DefaultSolrCoreState:214 - Running recovery - first canceling any ongoing recovery
2013-02-28 15:04:58,625 INFO org.apache.solr.cloud.RecoveryStrategy:217 - Starting recovery process. core=metadata recoveringAfterStartup=true
2013-02-28 15:04:58,626 INFO org.apache.solr.common.cloud.ZkStateReader:295 - Updating cloud state from ZooKeeper...
2013-02-28 15:04:58,628 ERROR org.apache.solr.update.UpdateLog:957 - Exception reading versions from log
java.io.EOFException
at org.apache.solr.common.util.FastInputStream.readUnsignedByte(FastInputStream.java:72)
at org.apache.solr.common.util.FastInputStream.readInt(FastInputStream.java:206)
at org.apache.solr.update.TransactionLog$ReverseReader.next(TransactionLog.java:705)
at org.apache.solr.update.UpdateLog$RecentUpdates.update(UpdateLog.java:906)
at org.apache.solr.update.UpdateLog$RecentUpdates.access$000(UpdateLog.java:846)
at org.apache.solr.update.UpdateLog.getRecentUpdates(UpdateLog.java:996)
at org.apache.solr.cloud.RecoveryStrategy.doRecovery(RecoveryStrategy.java:256)
at org.apache.solr.cloud.RecoveryStrategy.run(RecoveryStrategy.java:220)

2013-02-28 15:05:01,857 INFO org.apache.solr.cloud.RecoveryStrategy:399 - Begin buffering updates. core=metadata
2013-02-28 15:05:01,857 INFO org.apache.solr.update.UpdateLog:1015 - Starting to buffer updates. FSUpdateLog

2013-02-28 15:05:01,857 INFO org.apache.solr.cloud.RecoveryStrategy:126 - Attempting to replicate from http://23.61.21.121:65201/solr/metadata/. core=metadata

2013-02-28 15:05:02,882 INFO org.apache.solr.handler.SnapPuller:305 - Master's generation: 6993
2013-02-28 15:05:02,882 INFO org.apache.solr.handler.SnapPuller:306 - Slave's generation: 6993
2013-02-28 15:05:02,882 INFO org.apache.solr.handler.SnapPuller:307 - Starting replication process
2013-02-28 15:05:02,893 INFO org.apache.solr.handler.SnapPuller:312 - Number of files in latest index in master: 422
2013-02-28 15:05:02,897 INFO org.apache.solr.handler.SnapPuller:325 - Starting download to /solr/nodes/node1/bin/../solr/metadata/data/index.20130228150502893 fullCopy=true

2013-02-28 15:33:55,848 INFO org.apache.solr.handler.SnapPuller:334 - Total time taken for download : 1732 secs (The size of index files is 94G)