Thursday, October 30, 2008

Azure Storage - CloudDrive SDK

If you are the CloudDrive Powershell extension in the CTP of Azure Storage SDK, the easiest way to map a drive onto the cloud is to add this line to the MountDrive1.ps1 file:

MountDrive -ServiceUrl "" -DriveName "BigDrive" -ProviderName "BlobDrive" -Account "accountName" -Key "XXXXXXXXXX"

Note that the accountName is the name of your project on the Azure web site, the storage project name. And the Key is the primary key you are given from the Azure web site. Also, the SeriveURL doesn't contain your account name at the beginning. Once you have this line added to the bottom of the file and save, you can run the runme.cmd batch file from the command line and your drive will be mapped.

The other two lines look like this:

MountDrive -ServiceUrl "" -DriveName "Blob" -ProviderName "BlobDrive"

MountDrive -ServiceUrl "" -DriveName "Queue" -ProviderName "QueueDrive"

and represent the local storage, which is used to test your storage application -- in this case CloudDrive. CloudDrive is a powershell extension. As an example, it is very limited -- a better example of how to write a power shell extension then how to interact with CloudDrive storage.


Wednesday, October 8, 2008

varchar(max) and varbinary(max) Questions and Answers

How big of an allocation does max represent in the case of varchar(max) and varbinary(max)?

2 ^ 31 - 1 bytes or just about 2gb.

Can I specify a varchar(9000) or varbinary(12000)?
No.  If you are going to specify an actual number instead of (max) then your limit is 8000.  The size can be 1 to 8000, or max, there is nothing between 8000 and max.

Is a varchar(max) or varbinary(max) column stored in the data row?
If the size of the varchar or varbinary item is less than 8000 then it is stored in the data row. 
If it is greater than 8000 then the item is moved out of the data row into a special storage location for large objects.

Should varchar(max) be used to replace the TEXT column type?

Yes.  varchar(max) can handle larger strings than the text type can.  varchar(max) is easier to update than text with standard SQL statements.