Insufficient data from Andrew Fryer

The place where I page to when my brain is full up of stuff about the Microsoft platform

SQL Server 2008, TechNet Road-show answers

Following Tuesday’s TechNet event in Manchester, I promised to answer the questions in my blog that I couldn’t answer immediately, so without further ado…

Does data collector work with all editions specifically express edition? 

Data collection is where historical performance information is collected and stored in a database.  It was introduced in SQL Server 2008 and doesn’t work in earlier versions.  To answer the question, No, statistics cannot be gathered  for express edition nor can it be the home for the data collection database (aka performance warehouse, management data warehouse).

Compression and Transparent Data Encryption (TDE)

I got into a bit of a discussion at the end of the event about whether there was any benefit in compressing data in an encrypted database. Data compression works before the data is encrypted and both occur before the data is written to disk.  However backup compression won’t work well, because that will read the encrypted data and try and compress that which could actually make it bigger as there are no repeatable patterns in encrypted data for the compression algorithm to work with.

BTW while I am on this subject TDE doesn’t increase the size of the database and you can expect about a 5% cpu hit for using it.

SAN support

Our support team don’t care what SAN you have to run SQL Server 2008 on. It’s not a case of not working on certain SANs, it will just be slow if it’s not configured properly. In fact one of my friends on the support desk was telling me that one customer was filling up each of the disks in their SAN in turn and so were not getting the performance of reading across all the disks in the SAN.

GeoClustering support

Clustering isn’t currently supported across different subnets, and I haven’t found out when it will be supported, so this will have to wait for another post. I have to confess this flawed me at the event as it’s embarrassing that somebody knew about this, and none of of my normal SQL spies in the office knew (T-shirt to whoever it was, if you tell me who you are).

If you were there and I have missed anything please drop me an e-mail.