Is Spanning VMDKs Using Windows Dynamic Disks a Good Idea?

I've had several folks ask me recently about how to support very large NTFS volumes on vSphere virtualized Windows servers.  The current limitation for a VMDK in vSphere 5.1 is 2TB minus 512B.  FWIW, a Hyper-V virtual disk in Windows Server 2012 can be up to 64TB.  Those asking the question want to support NTFS volumes greater than 2TB for a variety of purposes - Exchange databases, SQL databases, and file shares.  Windows (depending on the version and edition) can theoretically support NTFS volumes up to 256TB (depending on cluster size and assuming GPT), with files up to 256TB in size (see … [Read more...]

Storage Basics – Part VII: Storage Alignment

At the risk of beating a dead horse, it's time to resurrect my Storage Basics series.  I've recently had some great feedback on the series and figured I should round out a few of the concepts before I wrap it up.  I want to cover a topic often discussed amongst virtualization professionals, but one I often find general practitioners and server admins not understanding: storage alignment.  Storage alignment, or the lack of alignment, is not a new issue and is not unique to VMware or virtualization in general.  However, the effects of misaligned storage can be more greatly felt in terms of … [Read more...]