Storage Basics – Part IX: Alternate IOPS Formula

It's been a long time since I published an article in my Storage Basics series - the series has been some of the top content on my site to date.  I sat for a beta version of the VMware Certified Advanced Professional - Desktop Design (VCAP-DTD) test today and was reminded by the test of a post I had in waiting about an alternate way to calculate IOPS (hint hint - memorize these formulas).  I have several more articles sitting in draft form, but a new job, crazy kids, home improvement projects, and a wife with chronic cerebral spinal fluid (CSF) leaks (it sounds bad - and it is - but look on … [Read more...]

iSCSI Bug – Traffic Routed Out Wrong Interface – Update

One of my most popular posts to date has been 'vSphere 5 Networking Bug Affects Software iSCSI' with some 20,000 page views and a bunch of comments.  The problem is a bug that causes vmkernel traffic (including iSCSI) to be sent out the unused/inactive/null NIC on a vSwitch with a manual failover order and Active and Unused vmnics.  It still appears that the issue I covered is affecting customers - we just had a new Clearpath customer call for help with this very issue.  VMware's KB on the issue … [Read more...]

vSphere 5 Networking Bug Affects Software iSCSI

Update 1: This issue was fixed as of 3/15/2012 in ESXi 5.0 Update 1 per the original knowledge base article: VMware KB 2008144. To download ESXi 5.0/vCenter Server 5.0 Update 1, see the VMware Download Center.  Update 2 (Nov 7 2012): While VMware says the issue was fixed in vSphere 5.0 Update 1, I have not found this to be the case.  I've had several environments where the bug was still present, and in some cases this nasty bug still appeared when implementing the Failback = NO setting on the vSwitch.  Additionally, setting Failback = No may cause some other problems - see my update here … [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...]

IBM DS3300 iSCSI Write Performance Solved

I have been pulling my hair out with a small VI3 implementation running against an IBM DS3300 iSCSI array.  Performance, for lack of a better term, sucked.  Granted, the DS3300 is not an enterprise level workhorse of a storage system, but it fit the budget.  Read performance was decent from the array, but write performance was terrible, maxing out at 10Mpbs throughput and insanely high latencies on long writes when the system was under load.  This led to some long P2V operations, poor guest performance, and some questions from the project sponsors on why I couldn't make the environment … [Read more...]