Restore Databases Instantly with SQL Virtual Restore - Red Gate ...

Background
SQL Virtual Restore allows users to restore
databases without allocating the storage space that
would usually be required, creating a fully-functional
database which uses the backup file or files as the
primary data source. SQL Virtual Restore works
with SQL Server native backups (both compressed
and uncompressed), and with backups created
using Red Gate’s SQL Backup Pro or SQL
HyperBac. SQL Virtual Restore runs through the
HyperBac engine.
You do not need to alter or otherwise configure your
backup operations. This is the case whether you’re
taking native backups or making backups with Red
Gate’s tools.
A distinct advantage of SQL Virtual Restore is that
it can be used for backup verification, as well as
1
object level recovery and disaster recovery. Backup
verification with SQL Virtual Restore involves a
comprehensive test of a backup file, by creating a
virtual restore in the background and performing a
full integrity and consistency check on the resultant
virtualized database using DBCC CHECKDB. This
process checks the physical integrity of the pages
in the backup file and the logical integrity of each
object in the database; a RESTORE VERIFYONLY of
the backup set alone checks only that all pages are
contained in the backup file.
There are a number of advantages to backup
verification with SQL Virtual Restore:
• It takes much less time than an equivalent full
restore and DBCC CHECKDB, fitting comfortably in
most maintenance windows.
• It requires a near-zero data footprint.
• It’s fully scriptable using native T-SQL commands,
making it an easy addition to any backup/
maintenance program.
• The entire verification process can be offloaded
to a second server, removing any maintenance
overhead from the production server.
Backup verification is only one of many uses for
SQL Virtual Restore, but it’s a particularly important
one for early detection of production integrity issues
and to ensure successful disaster recovery.
Moreover, performing best practice backup
verification prepares your backup files so that you
can restore them as fully-functional, fully-available,
completely-recovered databases instantly, at any
point in the future.
Restore Databases Instantly
A backup verification operation using SQL Virtual
Restore involves the same set of steps needed to
make a backup file instantly available in the future.
When performing a virtual restore, the native SQL
Server RESTORE DATABASE sequence is
completed. This includes the recovery phase, where
changes made during the backup process are
applied to the virtual database, so that it includes
an exact representation of the data as it existed at
the end of the backup. SQL Virtual Restore creates
several files during this process:
• ‘Virtual’ data and log files (.vmdf, .vdnf, .vldf)
These files are used by SQL Server during recovery
and for any write activity to the virtual restore.
• Virtual restore index files
The backup file is indexed during the virtual restore
process, so that data can be quickly accessed from
the backup when the virtually restored database is
online.
These files have a minimal data footprint, in many
cases just a few MB. Along with the backup file
itself (or backup files, if you are striping backups),
these files provide you with all the necessary
components to restore your database instantly, with
1 Object level recovery is the process of extracting data (rows or entire tables or views), discrete objects, or object definitions from backup archives
without performing a full RESTORE operation.
2