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...]

vCenter Database Stats Rollup Troubleshooting

VMware vCenter collects performance statistics, tasks and events for historical performance analysis and auditing.  The collection level and retention of performance statistics can be controlled through the vCenter GUI (see Administration | vCenter Server Settings | Statistics).   The level of statistics collection and retention periods can have a dramatic impact on your vCenter Server's performance if not carefully planned and monitored.  In particular, the vCenter database can grow quite large and the database server required to support the increase in statistics increases in size and … [Read more...]

Balloon Driver Problems with SQL

I have been meaning to write this up for a while; Scott Drummonds' 'Love Your Balloon Driver' post today at his Virtual Performance blog gave me a nice reminder.  I actually caught a sneak peak at the graphs with an explanation from Scott at his instructor-led lab at VMworld 2009.  Scott calls out that the only workload they discovered suffers from balloon driver activity is Java.  The reason for Java's problems with balloon driver activity is that Java itself runs in a VM and so the guest OS cannot properly determine which pages should be swapped out when the balloon driver calls for … [Read more...]

Virtualization Bookmarks for August 28th

Here are some bookmarks for resources that I have recently referenced: vCenter 4 and ESX 4 Now Use 10 Year Default SSL Certificate | VM /ETC - Rich Brambly has some guidance on installing a new SSL certificate on vCenter, with very useful links in his post to official VMware documentation and KB's on the subject. VMware vSphere Client on Microsoft Windows 7! | Virtual Lifestyle - Heiko Verlande has found a way to run the VMware vSphere Client on Windows 7. Virtu-Al » PowerCLI: Daily Report V2 - Version two of a handy PowerShell based VMware Environment Daily Report from VMware vExpert … [Read more...]