Friday, August 27, 2010

SQL Deployment versus File System Deployment in SSIS

This is another common question we face many times "Should I store my SSIS Packages to File System or on SQL Server?"
There are two places you can store your packages: on the file system or in the msdb database. Each storage option has its own pros and cons and which option you choose will be based on what is more important to you. We’ll cover these pros and cons in much depth in this section but to summarize, the following table gives you a high-level idea of which storage option is best based on the what functionality you’re most interested in. Just because a given storage option is not checked, does not mean it doesn’t have that functionality. The ones checked just are most optimized for the given functionality.

If security concerns you greatly, you may want to consider placing your packages in the msdb database. To secure your packages on the file system, you could have multiple layers of security by using the Windows Active Directory security on the folder on the file system where the packages are at. You could also then place a password on the packages to keep users that may have administrator rights to your machine from executing the package. This does add extra complexity to your package deployments in some cases. If you store your packages in the msdb database, you can assign package roles to each package to designate who can see or execute the package. The packages can also be encrypted in the msdb database, which strengthens your security even more.
Backup and recovery is simpler with storing your packages in the msdb database. If you were to store your packages in the msdb database, then you must only wrap the msdb database into your regular maintenance plan to backup all the packages. As packages are added, they are wrapped into the maintenance plan. The problem with this is that you can restore a single package using this mechanism. You’d have to restore all the packages to a point in time, and that would also restore the jobs and history. The other option is a file system backup, which would just use your favorite backup software to backup the folders and files. If you did this, you must rely on your Backup Operator to do this for you, which makes some uneasy. You could though at that point, restore individual packages to a point in time. In reality, you may just go ahead and redeploy the packages from Source Safe if you couldn’t retrieve a backup file. File system deployments are much simpler but less sophisticated. To deploy packages onto the file system, you must only copy them into the directory for the package store. You can create subdirectories under the parent directory to subdivide it easily. You can also copy a single package over easily as well in case you need to make a package change. To import a package into the package store using the msdb database, you must use Management Studio (or a command-line tool called dtutil.exe) and import them package by package. To do a bulk migration, you could use the deployment utility.
Along the same lines as deployment is troubleshooting. If something were to go bump in the night and you wanted to see if the packages in production were the same release as the packages you thought you had deployed, you must only copy the files down to your machine and perform a comparison using Source Safe or another similar tool. If the files were stored in the msdb database, you would have to right-click on each package in Management Studio and select Export. If the same packages were stored in the file system, you must only copy the files to your machine. Availability of your packages is always on the top of the list for DBAs. If you were to store the packages in the msdb database and the database engine were to go down, the packages are unavailable. If they were stored in the file system, then your packages would be available for execution. Of course, if the database engine is down, then probably one of your key data sources would also be down at the time. The good news is no matter what storage option you choose the performance will be the same. As you can see there are many pros and cons to each storage option and neither overwhelmingly wins. The main reason that we choose to use the file system generally is for simplicity of deployment.

Functionality Best in File System Best in MSDB
Security X
Backup and Recovery X
Deployment X

Execution Speed X X
Availability X

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