My IT Blog

When we troubleshoot performance related issues, the first think which would hit our mind it "Storage". So let's have a sneak peak about the basic troubleshooting of the storage related issues.  Poor storage performance is generally the result of high I/O latency. vCenter or esxtop will report the various latencies at each level in the storage stack from the VM down to the storage hardware.  vCenter cannot provide information for the actual latency seen by the application since that includes the latency at the Guest OS and the application itself, and these items are not visible to vCenter. vCenter can report on the following storage stack I/O latencies in vSphere.  Storage Stack Components in a vSphere environment GAVG (Guest Average Latency) total latency as seen from vSphere KAVG (Kernel Average Latency) time an I/O request spent waiting inside the vSphere storage stack.  QAVG (Queue Average latency) time spent waiting in a queue inside the vSphe...

I’m often asked the question when looking at vSphere statistics – “What is the difference between PCPU Used and PCPU Utilized and why don’t they match?” Let’s take a look as it can be somewhat complex. First lets start with some definitions: Time Stamp Counter (or TSC) – is a 64 bit register available on all modern processors that counts clock cycles at a consistent rate and is not affected by changes in clock frequency. Unhalted Cycles – another count of ‘all’ clock cycles, but this one is dependent on the clock frequency and therefore the rate can change if the clock frequency changes (due to things like power management or Hyper-Threading). Wall Clock Time – refers to elapsed real world time. Okay now lets define our two counters using the above definitions: PCPU utilized (which is TSC based) = (non-idle state TSC cycles)/wall clock time PCPU used (which is unhalted cycle based) = (unhalted cycles)/wall clock time So assuming a non Hyper-Threaded system, and no pow...

When you are debugging the Orchestrator related issues in mid/large deployments , it is expected that the server.log file rotates rapidly.  In this case we need to increase the log file size and the rotation interval. Below are the steps to make changes to the config file to capture large number of files for troubleshooting.  Config File Location :  Appliance deployment:  /etc/vco/app-server/log4j.xml Windows deployment:  <install_Location>\app-server\conf\log4j.xml Steps:  1. Edit the file  log4j.xml 2. Locate the  <appender class="org.apache.log4j.RollingFileAppender" name="FILE">  section 3. Increase the size of the log file to 10 MB   <param name="MaxFileSize" value="10240KB"/>    4. Increase the  number files to be retained before rotation  <param name="MaxBackupIndex" value="5"/> Cheers :-) 

Steps to configure the vCenter Server to generate SNMP traps: A.In the Home page of vSphere Client B.Select vCenter Server Settings  C.Select SNMP configuration D.Enable one of the SNMP receivers E. Provide the details for :  Receiver URL : Provide the host name of the Management Server (target SNMP server / monitoring tool) which will be connected to the VMware vCenter Server. (VMware vCenter Server sends the SNMP traps to this Management Server) Configure port 162 as the SNMP port. Community String: Provide community string (default string is "public")  SNMP versions v1/v2/v3 are supported That is all that is needed for the configuration.  Now you need to configure alarm for generating SNMP traps in the vCenter server. When ever there is a change in the environment ( host state change, VM state change ,etc) the trigger will be generated and send an alert to the monitoring server.  Configure the Alarms After you have setup the external ...

VVols Perhaps the most wanted feature in vSphere 6 is Virtual Volumes, or VVOLs. VVOLs extends the VMware software-defined storage (SDS) story to its storage partners, and completely changes the way its hypervisor consumes storage; it radically changes how storage is presented, consumed and managed by the hypervisor. No longer is virtual machine (VM) storage bound by the attributes of the LUN, as each VM disk (VMDK) can have its own policy-driven SLA. VMware has a passel of storage vendors on board to equip its storage, with the ability to offer VVOLs storage to the VMware hypervisor. I'm sure this feature will get much press and customer attention in the coming days. vMotion vSphere vMotion just got 10 times better, and a lot more interesting. For one thing, it supports live VM migration  across vCenter servers, and over long distances. It used to support round trip times (RTTs) of 10 ms, but now supports RTTs of 100 ms. A ping from Portland, Ore., to Boston, Mass., is 90 ms;...

Here is a list of feature comparison of 5.5 and 6.0

Today we had a (friendly ;-) ) conversation with my colleagues which moved to an argument about the cloud computing. We were discussing (arguing) about the types of cloud services and its pro's / con's which lead me to write this blog post.  The Cloud Computing is now a trend and a hot discussion in every IT group.  The reason behind is that the cloud infrastructure can offer advantages over traditional datacenters in the areas of performance, scalability, and even security. There is a vast differences between private, public and hybrid clouds for enterprise. The type of cloud service is defined based on the types of data they store.  Sometimes these differences narrow, but each type of cloud has different levels of security and varying degrees of management. One may be more flexible or scalable, while another might be more affordable.  Here we’ll talk about private, public and hybrid cloud computing and some of their primary differences. What is a public clo...