To add to Erland's response, below is the relevant information from the SQL
2000 Books Online. Basically, SQL Server and your storage solution need to
communicate using the SQL Server virtual device interface (VDI) in order to
coordinate the snapshot backup timing. Your storage solution needs to
support this API for reliable snapshot backups of SQL Server databases.
<Excerpt href="adminsql.chm::/ad_bkprst_2upf.htm">
The snapshot backup and restore functionality is accomplished in cooperation
with third party hardware and/or software vendors. These vendors use
features of SQL Server 2000 designed for this purpose. The underlying backup
technology creates an instantaneous copy of the data being backed up. This
is typically accomplished by splitting a mirrored set of disks or creating a
copy of a disk block when it is written, preserving the original. At restore
time, the original is made available immediately and synchronizing the
underlying disks is done in the background, resulting in almost
instantaneous restores.
</Excerpt>
--
Hope this helps.
Dan Guzman
SQL Server MVP
"Bernhard Krautschneider" <be*********************@acp.at> wrote in message
news:de**************************@posting.google.c om...
Erland Sommarskog <so****@algonet.se> wrote in message
news:<Xn**********************@127.0.0.1>...
Bernhard Krautschneider (be*********************@acp.at) writes: is it possible to do a storage snapshot of a running ms-sql database
without losing transactions?
What tasks must be done before such a snapshot.
Not sure what you mean. Are you talking about snapshot replication? Or
do you mean taking a backup? In the latter case, the answer is yes. BACKUP
in SQL Server is designed to be run on a live database - anything else
would be unacceptable for a 24/7 shop.
The storage I use is able to do a snapshot-copy of all disks to
another storage device. The problem is, that while you do this
snapshot, the database has to be in a consistent state to be usable as
a disaster solution. Within oracle you could do that via the "begin
backup"-clause.
Bernhard