Kevin Kline : Virtualization

The All-New 'Database Lifecycle Management" is available on MSDN

KKline — Fri, 05 Apr 2013 10:51:00 GMT

The Database Lifecycle Management is an MSDN curated content view providing a single location to find many of the best solutions for common customer tasks in Microsoft SSDT, SSMS, and SQL Database....(read more)

Let's Talk Licensing and Virtualization for SQL Server

KKline — Thu, 13 Dec 2012 19:23:00 GMT

Kevin details many new developments with SQL Server virtualization and licensing....(read more)

PASS Summit 2012, Slide Decks

KKline — Mon, 12 Nov 2012 17:02:00 GMT

Get the latest slide decks from Kevin Kline's presentations at the PASS Summit 2012 conference....(read more)

Conquer Your Fear of Virtualization with a Free Day of Training at PASS!

KKline — Thu, 18 Oct 2012 16:50:00 GMT

Get tons of free training from House of Brick, one of the USA's top database and virtualization consultancies, at the 2012 PASS Summit!...(read more)

The Expert's Conference (TEC) - For AD, SharePoint, Exchange, PowerShell and Other Admins

KKline — Mon, 19 Mar 2012 13:09:00 GMT

The Expert's Conference (TEC) - For AD, SharePoint, Exchange, PowerShell, Microsoft Hyper-V, and Other Admins...(read more)

New on "Database Trends & Applications"

KKline — Tue, 16 Aug 2011 19:37:00 GMT

In last month's column, "2012 Might Really Be the End of the World as We Know It," I described a number of major developments in the IT industry that are likely to disrupt the life of database professionals everywhere...(read more)

What I'm Reading, July 22 2011

KKline — Thu, 21 Jul 2011 14:43:00 GMT

I read too much, and that, my friends, is an entirely separate topic for a blog post. But I thought I'd share with you a little more about what I'm reading because sometimes, if I'm lucky, it might be something you'd enjoy too. So I'm going to start sharing...(read more)

Microsoft Windows Platforms Blog Watch

KKline — Wed, 20 Jul 2011 14:44:00 GMT

Remote Desktop Services Component Architecture Poster Grab your own poster! A visual guide to key Remote Desktop Services technologies in Windows Server 2008R2 Virtually Free Get the latest update rollup package for the Hyper-V role in Windows Server...(read more)

Got a slow holiday seaons? Why not spend it learning?

KKline — Thu, 31 Dec 2009 18:40:00 GMT

Traditionally, the time between Christmas and New Years is a bit slow. Many people take time off from work and, for those of us still working, it's a good time to catch up on all of those low priority projects that have been on the back burner for the...(read more)

New at SQLMag - Disk2Vhd

KKline — Fri, 09 Oct 2009 17:01:00 GMT

I just posted a new entry on my SQLMag Tool Time blog that you might enjoy. Thanks to my friend and fellow MVP John Paul Cook for bringing Disk2Vhd to my attention on his blog . The free tool is enables migration of a physical machine (PM) to a virtual...(read more)

Clock Drift in Virtualization

KKline — Mon, 25 Aug 2008 20:44:00 GMT

Last week, I was listening to John Rives, CEO of Amniox, speak about virtualization and clustered VMS (see pictures at http://drsql.spaces.live.com/blog/cns!80677FB08B3162E4!2292.entry. Thanks Louis!) at the local SQL Server User Group meeting in Nashville.

John gave a really interesting talk about implementing virtualization and many of the benefits and pitfalls that you might encounter. Most of the content was review for me, but the one concept that was new was a biggee - clock drift.

Clock drift is a situation in which the actual time shown on the physical machine's (PM) clock, for example 3:53 pm today, is no longer in sync with one or more of the clocks of virtual machines' (VM) running on the PM, showing 12:12 pm today and 9:30 pm yesterday. This can happen because the VMs 1) only receive a slice of the PM's total processing power and cycles, thus getting confused on the time, and 2) the application(s) running on the VM do not manually synchronize the VM clock with the PM's clock or an external time source. Naturally, if you're running SQL Server, this can be a huge data integrity problem for you - especially for any transactions that record the date and time.

This is a fairly old-school problem, it turns out, and there are lots of hits when you google for "clock drift virtualization". However, the state of the industry seems to be somewhat immature in that the best hits tended to be blogs and discussion forums rather than vendor documentation or best practices papers. If you're developing applications for SQL Server that might be implemented on a VM, do yourself a favor and make sure you include clock syncronization processes as part of the application. Otherwise, you might have to deal with a nasty clock drift problem.

Regards,

-Kev