If you lose the hard disk
containing the storage group databases, you can replace the damaged
disk and then restore the most recent database backups. If you then
delete the checkpoint file, then an automatic log file replay of all
transactions that occurred after the backup transfers and recorded
transactions from log files to the databases. This is known as a
roll-forward or a soft recovery.
It is possible that
transaction log files were backed up subsequent to the database file
backup. Transaction files are typically much smaller than database
files and are backed up more regularly. An incremental backup backs
up all the information that has been written to the transaction log
since the last full or incremental backup. A differential backup
backs up all the transaction log files whether they have been
previously backed up or not. Neither incremental nor differential
backups delete the transaction log files, nor do they backup the
database files.
If you have backed up
transaction log files since the last full backup, you can perform a
hard recovery. Hard recovery is the process of replaying transaction
log files from the backup medium after you restore a database from an
online backup.
To know more about backup
and recovery, you need to do a course in system administration. SLA
IT Employment Training Company in Chennai conducts courses in MCSA
and MCSM. Drop in at SLA for a free career counselling. For
more details visit SLA Chennai
or dial (91
44) 4200 5050/90.
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