Sudden increase in Page Writes/s after patching / rebooting I was given a SQL Server 2008R2 to run, but my DBA skills are rusty after some years away from the day-to-day ops, so please bear with my (somewhat) silly questions.

This SQL Server is running in Azure with 14GB RAM, 8 cores and 3 sets of striped disks (two stripes per set).

Whenever I have to apply an Update and reboot the machine, Users experience a MAJOR system slowdown during the first 20/30 minutes of the next business day.

In ALL occasions I was online inspecting the behaviour, the only significant change I could detect was a sudden increase in Page Writes/s.  Further investigation pointed to a sudden increase in TEMPDB i/o ops.  I have then tried to increase TEMPDB's base size, but this still happens.  Event Viewer logs report nothing.  It's like SQL Server needs to "re-tune" itself under load after reboot.

As I said, the slowdown lasts for 30 minutes tops, but it is obviously annoying and I can't figure out a way to prevent it. 

Any ideas?

Thanks in advance,
When you restart the service or reboot, the buffer pool and plan cache get wiped out as a result, and so when the server starts back up again, they don't get loaded until users start executing queries. 

What you can do to mitigate this is have a stored procedure aimed at simply running some queries that will load up your most frequently-used data into memory. Call that procedure after a restart, and you will feel that initial delay instead of your users.