Sql-server – Backup Compression in SQL Server 2005

Never heard such rubbish.

FULL or BULK LOGGED mode means you require log backups. SIMPLE means you don't. You always require full backups.

Copying the MDF and LDF files isn't a backup and can potentially lose** you data if you are in a transaction as you shut SQL Server down.

If the mdf files are missing it means they aren't there because of finger trouble or this "backup" method. You can't lose mdfs unless someone removes the files or removes a drive when SQL Server is shut down

** Edit:

By losing data I mean "open transactions won't be committed". Typically, client code won't handle a retry and, say, log the error but not the data to be written.

Any data in committed transactions, no matter how old or new, will be safe

DBCC SQLPERF (LOGSPACE) will return the size of the log file in MB & the current percentage used. From that you can calculate the current utilised portion of the log file in MB.

That by itself will not be sufficient to calculate log backup size, not least because you are using backup compression. However collecting this data over time & correlating it with the size of the backups might reveal a linear relationship.

You could insert a step into the Log Shipping backup job to record the size of the utilized portion of the log file and a another step after the backup to record the new size of the log file and the size of the backup.

Running this for a period and analyzing the results could allow you to estimate the size of the backup file.

Not the most straight forward method and to be honest it might not even work. If you are interested in giving it a go I would be interested in helping.