EMC SourceOne Index issues

Hi,

I have deployed SourceOne 6.7 SP2. The environment contains 2 Clustered Master machines. The 2 other machines contains Worker, Web and archive roles. Index location is at NAS and both Native Archive machines writes on the same location.

Now I am facing issue with index gets corrupt regularly and re-index needs to be run almost every week. Following error comes

ExAsIdxObj Found Index: Journal\Journal\201201\20120127180124\\\win_nas\index\Journal\201201\026 in DB but failed to Find it on Disk: \\win_nas\index\(0x8604282C) [ExAsIndex.exe, ExAsIndexPoll.cpp(1214).CExAsIndexPoll::GetIndexPtr]

After re-index the error goes away and everything comes up normal.

Any idea how to prevent this error to come again? as due to corrupt index the search application doesnt work correctly.

Regards,

Atif