title: Oracle 11G export error (Ora-01115: IO Error reading block from file 6 (block $ 75593959)
body: <p>I have oracle 11G installed on Windows 2008 Server. I have a big file table space of 700GB. I have all the data/tables in a single user "ARCHIVE". While exporting the database with <code>exp</code> command. It produces the following errors:</p>
  
  <pre><code>EXP-00056: ORACLE error 1115 encountered
  ORA-01115: IO Error reading block from file 6 (block # 75593959)
  ORA-27070: async read/write failed
  ORA-04016: Error queuing an asynchronous I/O request.
  O/S-Error: (OS 23) Data error (cyclic redundancy check)
  </code></pre>
  
  <p>What is the safe method to export my database?</p>
  
  <pre><code>===================expdp output starts=========================
  ;;; 
  Export: Release 11.2.0.1.0 - Production on Fri Sep 18 09:19:59 2015
  
  Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.
  ;;; 
  Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
  With the Partitioning, OLAP, Data Mining and Real Application Testing options
  Starting "ARCHIVE"."SYS_EXPORT_SCHEMA_02":  archive/******** schemas=archive directory=backup_dir dumpfile=bck_180915 logfile=expdplog compression=all 
  Estimate in progress using BLOCKS method...
  Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
  Total estimation using BLOCKS method: 703.8 GB
  Processing object type SCHEMA_EXPORT/USER
  Processing object type SCHEMA_EXPORT/SYSTEM_GRANT
  Processing object type SCHEMA_EXPORT/ROLE_GRANT
  Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
  Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
  Processing object type SCHEMA_EXPORT/TABLE/TABLE
  Processing object type SCHEMA_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT
  Processing object type SCHEMA_EXPORT/TABLE/INDEX/INDEX
  Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
  Processing object type SCHEMA_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
  Processing object type SCHEMA_EXPORT/TABLE/COMMENT
  Processing object type SCHEMA_EXPORT/PROCEDURE/PROCEDURE
  Processing object type SCHEMA_EXPORT/PROCEDURE/ALTER_PROCEDURE
  Processing object type SCHEMA_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
  ORA-31693: Table data object "ARCHIVE"."TBL_MATRIC_DATA" failed to load/unload and is being skipped due to error:
  ORA-02354: error in exporting/importing data
  ORA-01115: IO error reading block from file 6 (block # 54124632)
  ORA-27070: async read/write failed
  OSD-04016: Error queuing an asynchronous I/O request.
  O/S-Error: (OS 23) Data error (cyclic redundancy check).
  ORA-01115: IO error reading block from file 6 (block # 54124632)
  ORA-27070: async read/write failed
  OSD-04016: Error queuing an asynchronous
  ORA-31693: Table data object "ARCHIVE"."TBL_INTER_DATA" failed to load/unload and is being skipped due to error:
  ORA-02354: error in exporting/importing data
  ORA-01115: IO error reading block from file 6 (block # 75593959)
  ORA-27070: async read/write failed
  OSD-04016: Error queuing an asynchronous I/O request.
  O/S-Error: (OS 23) Data error (cyclic redundancy check).
  ORA-01115: IO error reading block from file 6 (block # 75593959)
  ORA-27070: async read/write failed
  OSD-04016: Error queuing an asynchronous 
  . . exported "ARCHIVE"."SYS_EXPORT_SCHEMA_01"            31.76 KB    1122 rows
  . . exported "ARCHIVE"."MISSING_RANGES"                  5.984 KB     102 rows
  . . exported "ARCHIVE"."RANGES"                          4.968 KB      10 rows
  Master table "ARCHIVE"."SYS_EXPORT_SCHEMA_02" successfully loaded/unloaded
  ******************************************************************************
  Dump file set for ARCHIVE.SYS_EXPORT_SCHEMA_02 is:
    BCK_180915.DMP
  Job "ARCHIVE"."SYS_EXPORT_SCHEMA_02" completed with 2 error(s) at 20:38:19
  
  ====================expdp output ends =========================
  </code></pre>