It is used to set the optimal length of a rollback segment.

 It  will  try  to  fit  the transaction in a cyclic fashion to all existing extents.  Once it found an extent is in use then it forced to acquire a new extent (No. of extents is based on the optimal size)

 Limit the number of extents in the tableSeparate Table from its indexes.Allocate Sufficient temporary storage.

 Calculate the total header sizeCalculate the available dataspace per data blockCalculate the combined column lengths of the average rowCalculate the total average row size.Calculate the average number rows that can fit in a blockCalculate the number of blocks and bytes required for the table. After  arriving the calculation, add 10 % additional space to calculate the initial extent...

 Database overall physical architecture is maintained in a file called control file.  It will be used to maintain internal consistency and guide recovery operations. Multiple copies of control files are advisable.

 Process of having a copy of redo log files is called mirroring. This  can be achieved by creating group of log files together, so that LGWR will  automatically  writes  them to all the members of the current on-line redo  log  group. If any one group fails then database automatically switch over to next group. It degrades performance.

 Shadow  set of disks save as a backup in the event of disk failure. In most Operating  System if any disk failure occurs it automatically switchover to place of failed disk. Improved performance because most OS support volume shadowing can direct file  I/O request to use the shadow set of files instead of the main set of files. This reduces I/O load on the main set of disks.

 It  is  a  measure  of  well the data cache buffer is handling requests for data. Hit Ratio = (Logical Reads - Physical Reads - Hits Misses)/ Logical Reads.

 When Segment is dropped.When Shrink (RBS only)When truncated (TRUNCATE used with drop storage option)

 We  should  depend  on  export/import  utility  for  backup/recovery (fully reliable) The tar command cannot be used for physical file backup, instead we can use dd command which is less flexible and has limited recoveries.

 The space used transaction entries and a deleted record does not become free immediately after completion due to delayed cleanout. Trailing nulls and length bytes are not stored.  Inserts of, updates to and deletes of rows as well as columns larger than a single datablock, can cause fragmentation and chained row pieces.

 To give the export file name.

 Flag  to  indicate  whether export should compress fragmented segments into single extents.

 A  flag  to  indicate whether grants on databse objects will be exported or not. Value is 'Y'  or 'N'.

 A flag to indicate whether indexes on tables will be exported.

 Flag  to  indicate  whether  table rows should be exported. If 'N' only DDL statements for the database objects will be created.

 A flag to indicate whether constraints on table need to be exported.

 A flag to indicate whether full databse export should be performed.

List of table accounts should be exported.