What is NAS, SAN, DAS ?

NAS stands for Network Attached Storage. It differs from traditional, directly attached storage in that, in NAS, the operating system and other software on the NAS product are dedicated solely to data storage.

SAN stands for Storage Area Network. A SAN is a network designed to attach storage hardware and software to servers. SANs generally come in two forms: as a network primarily dedicated to transferring data between computer systems and storage systems, or as a complete system that includes all of the storage elements and computer systems within the same network.

DAS stands for Directly Attached Storage. DAS is generally used to differentiate between storage systems directly attached to a server or workstation and NAS and SAN setups.


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How to fix orphaned SQL Server users?

The problem is that the user in the database is an "orphan". This means that there is no login id or password associated with the user. This is true even if there is a login id that matches the user, since there is a GUID (called a SID in Microsoft-speak) that has to match as well.

This used to be a pain to fix, but currently (SQL Server 2000, SP3) there is a stored procedure that does the heavy lifting.

All of these instructions should be done as a database admin, with the restored database selected.

First, make sure that this is the problem. This will lists the orphaned users:

EXEC sp_change_users_login 'Report'

If you already have a login id and password for this user, fix it by doing:

EXEC sp_change_users_login 'Auto_Fix', 'user'

If you want to create a new login id and password for this user, fix it by doing:

EXEC sp_change_users_login 'Auto_Fix', 'user', 'login', 'password'


Source : SQL BLOG