How to run dbverify utility on datafiles which is in ASM storage.

Generally we will use dbvefiry utility to find any blocks has corrupted on datafile. but the files which is in ASM storage we need to include one more parameter named "userid" which accepts two arguments i.e username and password.

  
oracle:ortestdb@lnxrecov /oracle > dbv file=+DATA/ortestdb/datafile/users.411.795847253 blocksize=8192 userid=sys/*****

DBVERIFY: Release 10.2.0.4.0 - Production on Thu Oct 11 03:25:50 2012

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

DBVERIFY - Verification starting : FILE = +DATA/ortestdb/datafile/users.411.795847253

DBVERIFY - Verification complete

Total Pages Examined         : 25600
Total Pages Processed (Data) : 0
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 6
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 47
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 25547
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Highest block SCN            : 0 (0.0)
oracle:ortestdb@lnxrecov /oracle >

For ASM files if we don't use userid parameter then we will endup with error like below,

  
oracle:ortestdb@lnxrecov /oracle > dbv file=+DATA/ortestdb/datafile/users.411.795847253 blocksize=8192

DBVERIFY: Release 10.2.0.4.0 - Production on Thu Oct 11 03:36:46 2012

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

DBV-00008: USERID must be specified for OSM files