Sunday, December 22, 2013

Basic VMware Interview Questions

I suggest you all to know what it is, not necessarily how and why about a product for a entry level vmware interview. Addition to these questions (after you have found answers and want to know more) I suggest you to go to vmwarelearning.com and go through the basic vsphere and ESXi videos.

  1. what is virtualization?
  2. what is a esx or an esxi?
  3. what is a vcenter ?
  4. what is a vsphere client?
  5. what is a vsphere web client?
  6. what is ha?
  7. what is ft?
  8. what is the difference between ha and ft?
  9. what is vmotion?
  10. what is svmotion?
  11. what is hot add?
  12. what is hot plug?
  13. what is drs?
  14. what is dpm?
  15. what is EVC & its benefits?
  16. what is update manager?
  17. what is VDP?
  18. what is iscsi & scsi, whats the difference?
  19. what is raid 0/1/5/10?
  20. what is FC/FCOE?
  21. what is hba?
  22. what is a lun? 
  23. What is SR-IOV?
  24. What is NSX?
  25. what is vmware horizon view or desktop virtualization?
  26. what is vmware vcloud or cloud computing?
  27. what are the advantages of vdSwitch over standard vSwitch
  28. what is the first thing that you do when you have a host which shows up as disconnected in the vcenter server?
  29. how do you find the version of vcenter server or esxi host?
  30. how do you find the driver/firmware version of the nic/hba?
  31. how do you restart management services in esx/esxi ?
  32. how to enable/disable ha/drs/ft for a cluster?



If you come across any other then please let me know in the comment section below and I will be glad to add them here.

Sunday, December 15, 2013

Keep your e Device Alive and stop updating your apps

You might have wondered why does my PC or smartphone gets slow after a year or two even though its the same hardware and same OS. Re installation of the OS of the e device seems to be a temporary fix but after sometime you are still stuck with the same problem of the device or system being laggy. We should all remember that hardware is the resource and it is not actually meant for the Operating System (OS) like your android or windows OS to use it all but it is a platform on which the OS must sit be a the mediator to the applications which are installed in it and the underlying hardware resources. Most of the time the OS remains the same inspite of few updates but it is the applications which gets updated the most. If you are an android device owner then you know what I mean. Everyday a new device with more aggressive hardware comes out and the app developers want to move on and use all the resources that they can get so that they can give a better user experience. If it is a game app then more the resources > more the fun but unfortunately our hardware can't keep up with this new updated app which is designed for higher end devices (even thought it still can be installed and played but it will start to annoy you with its lagging and slow performance). It is like a Cadillac or a Range Rover running on a hyundai entry level car's engine. The vehicle will still move but its undrivable and unbearable. In other words you buy a hyundai entry level car and upgrade its body to cadillac or rangerover. So My suggestion is after a year of the purchase of your device which was released not more than an year ago you please stop updating your applications. So please dont overkill your device and stop updating apps after some time when you feel it has started lag and before you update any app make sure you check out the change log and what has it that has changed in this new version and do you really need it or can you live without it since it doesnt appeal to you.

Monday, December 9, 2013

SSO rolls back during the vcenter 5.5 installation or during an upgrade from 5.1

Issue: It is a fresh vcenter 5.5 install or an upgrade from vcenter 5.1.x, whether it is a simple install or individual component install the SSO server installation rollsback without any error.

Resolution 1: Go to
 \\VMware-VIMSetup-all-5.5.0-1312299\Single Sign-On\prerequisites
and make sure all the prerequisites are installed. This issue occurs due to the failure of the installer to install the VMware-python.msi

Resolution 2: Make sure your password doesnt contain ;"'^\ or a space in it.

If these doesnt work then you may try
https://communities.vmware.com/thread/458077

Tuesday, December 3, 2013

vmware update manager error "an internal error occured in the vsphere client. details: unable to connect to the remote server"

Issue: Unable to download and install the update manager plugin.

what worked:
uninstall the update manager,
rename the old update manager directory,
reinstall the update manager.

What didn't work:
http://IP address:9084/vci/downloads/vmware-umclient.exe is not accessible via the web browser.
http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&externalId=1014639
replaced the fqdn in upper case with the ip address but no go.
nslookup from the vcenter server to the vcenter server works.
while trying to enable the plugin it still gives the error
"an internal error occured in the vsphere client. details: unable to connect to the remote server."
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1020291
8084 and 8443 is working.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1003602
odbcad32.exe connections for the update manager are valid and tested ok.
the vcenter db was in the local vcenter VM but the update manager was in a different database.
created a new UMDB2 but no go.
pointed it back to the old original udpate manager but no go.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1039089
the connection to the database is successful.
http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=1034605
but no go.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1004680
uninstalled the update manager and deleted the existing update manager databases and started the reinstallation of the vmware update manager.

Wednesday, November 27, 2013

p2v fails with "FAILED: A general system error occurred: No connection could be made because the target machine actively refused it" error

p2v source machine: redhat 6.x. the p2v fails all the time eventhough the prerequisites are all met.
what worked : The issue was that you need swap partition as well to back it up. Once included swap partition, we were able to p2v.
what didn't work: http://www.vmware.com/support/converter/doc/conv_sa_51_rel_notes.html
there is only 1 job running for that source machine.
the source physical machine is redhat 6.1
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1010056
informed that the ports 22, 443, 902, 903 should be open between the source physical machine, destination vcenter server and the converter.
tried telnet from converter to the linux machine and 443,902,903 were blocked,
on the linux machine the firewall is disabled.
tried telnet from vcenter server to converter but still the ports were blocked.
http://www.symantec.com/business/support/index?page=content&id=TECH102416
informed the SEP uses the same port 443.

Friday, October 25, 2013

no performance data of esxi 5.x in the summary or the performance tab

symptoms:
  • cpu, memory usage is 0 in the summary tab in the vCenter and vWC (vsphere web client)
  • performance chart is blank for realtime or past history in the vCenter and vWC (vsphere web client).
  • vsphere client displays the cpu, memory usage and the performance data of the host.
Resolution: restart the host agents by ./sbin/service.sh restart, disconnect and connect the host from the vcenter by right clicking the host.
If the above doesnt work then try these below
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1032908
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=5296658
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1003878
 

Wednesday, September 25, 2013

Incident : esxi 4.x lun not detected.

Issue : Some of the esxi 4.x hosts arent seeing 2 luns.
What we tried:
suggested to connect to the host via vSphere client bypassing the vCenter server and try adding the luns retaining the same signature but it only gives an options to reformat it and the re-signature options are grayed out.
fdisk -l /vmfs/devices/disks/naa.<xxxxxxx>. The partition table was listed as vmfs (confirming whether the partition table was corrupt or not and it was not corrupt)
esxcfg-volume -M naa.<xxx> but it said no matching naa.<xxx> found!.
~ # esxcfg-volume -l
VMFS3 UUID/label: <xxxxxxxxxxxxxxxxxxxxxx> /NAS_ESX2
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: naa.600508b4000ad2c800004123452345346:1     range: 0 - 511743 (MB)

VMFS3 UUID/label: <yyyyyyyyyyyyyyyyyyyyyyyyyy>/NAS_ESX1
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: naa.600508b4000ad2c80000478675676578787:1     range: 0 - 511743 (MB)

~ # esxcfg-volume -M <xxxxxxxxxxxxxxxxxxxxxx>
Persistently mounting volume <xxxxxxxxxxxxxxxxxxxxxx>
~ # esxcfg-volume -M <yyyyyyyyyyyyyyyyyyyyyyyyyy>
Persistently mounting volume <yyyyyyyyyyyyyyyyyyyyyyyyyy>
issue resolved.

Tuesday, September 24, 2013

How Should you get VMware Certified Professional 5 - Infrastructure as a Service (VCP5-IaaS)

Assuming that you have already earned your VCP5-DCV and you are already aware of which is a per-requisite for this exam let us get on with the subject right away. 
If you have seen my VCP5-DT series then you will know that i like to begin with the blueprint first. so first and foremost download the vcp5-iaas blueprint from the vmware website.
Download all the pdfs which are mentioned in the blueprint.
Make a note of the product versions which are covered in the blueprint and then go get some CBTs online.
Apart from
and
I also highly recommend (not necessarily in the same order but if you can then all of them)
from VMware education services hosted on http://vmwarelearning.com/
Building a Lab with vCloud Director 5.1
VMware vCloud Director Installation 

Best Practices and Troubleshooting Guide for vCenter Chargeback Manager 2.5



SRM Incident : cannot selectively recover with array based replication

Issue: there are 2 VMs.
They want to bring down 1 of the 2 VMs in production storage system and bring it up in the DR site but while doing so it throws an error.
Test Recovery Plan
<aaaa.bbb.cccc.com>
Virtual machines [data.vmN-ame] that are not protected by this protection group use datastores [data.dsNa-me] that are in this protection group. <xxxx>\yyy aaaa.bbb.cccc.com>

T/S : checked the recovery group configuration and it seems okay.
Array based replication works for all the VMs in that array but not selectively for few VMs where they want to recovery only few of the VMs of the array excluding the others.
Currently we can either recover all the VMs in that array or none
Resolution: the error what he was getting was indicating that the hard disk 2 of the VM being recovered on the local storage is missing. Hence the only way was to either remove the vmdk from the vm or move the vm out of the datastore.

Wednesday, September 18, 2013

Everything about VMware vNetwork Distributed Switch ( VDS or dvswitch )

If you are moving to VMware vcloud or getting ready to get certified with VMware VCP5-IaaS then you must have realized how important it is to be aware of VMware networking concepts especially the VMware vNetwork Distributed Switch (VDS or dvSwitch) . I thought the same for myself and collated some of the materials that I am planning to go through and if you know I love videos more than text. So here you go....
VMware vSphere: Networking - Distributed Virtual Switch
VMware Networking | Creating a vSphere Distributed Switch
VMworld 2011: VSP3864 - Best Practices for Virtual Networking

Using the vSphere Distributed Virtual Switch dvswitch) 

Configuring LACP on a vSphere 5.1 Distributed Switch
Migrating VMs and ISCSI from vSS to vDS without service interruption in vSphere 5
VMworld 2011: VSP2894 - Virtual Distributed Switch Best Practices 
Creating a Distributed Virtual Switch and Portgroups with the vSphere Web Client 

additionally you might also like to see the following if you are not me...
If you are done with all these materials now you are an official rockstar with dvswitches...hell yeah !

Tuesday, September 17, 2013

How Should you get VMware Certified Professional 5 - Desktop (VCP5-DT)

Recently I got my VMware VCP 5 - DT and I think I should share what path one must take to get it. without further delay lets get on with the way to answer those 85 questions.

1. Know What you need to study

Get the VMware VCP5 - DT blueprint and download all the pdfs which are in that blueprint which will let you know what version of vmware view are you concentrating on for the exam.

2. Training Videos

A) Quality comes at a costUsually train signal has done a great job when it comes to training videos on the subject of vmware but for this it seems they have not kept their own standards. I have been told that the trainers fail to keep you interested in the subject especially if you don't like to see (or hear) your trainer yawn a few times during your training.
I highly recommend Mastering VMware View 5 and Preparing for the VCP510-DT Exam
by Greg Shields who is known for his very famous training videos for his networking certification videos (CCNA, CCNP etc.,) under cbtnuggets. The videos are presented in a very lively manner by gregg shields and especially for someone with a very short span of focus like me it greatly helped.

B)  Quality comes for free toowatch
What is Desktop Virtualization and VDI?

Make sure you watch and go through all these videos too on youtube. I recommend you to rather download them using a Video DownloadHelper addon in firefox and keep them for re view.
Deploying VMware View 5 - Part 1 Configure Active Directory and Deploy VMware Connection Server

 

Deploying VMware View 5 - Part 2 Configure Windows 7 to be a VMware View Desktop
Deploying VMware View 5 - Part 3 Creating a 'Manual Pool' and Connecting a View Client
Deploying VMware View 5 -Part 4 Installing and Configuring SQL 2008 R2 and VMware Composer
Deploying VMware View 5 - Part 5 Deploying Linked Clone View Desktops

 Now you are not done yet. Go to youtube and search exactly for these keywords "vmware view 5 vmworld" and under filters choose 20 minutes to show videos which are more than 20 minutes. Make sure you watch all these vmworld videos which are nearly an hour and they are worth it.
Once you are done doing all these you are ready to write the exam but if you want to excel in it then you might want to search for a many different vce files on the net as you can for vmware vcp 5 dt exam and understand each question and the answers for it. After this you can finish the exam in less than an hour even though it is meant for 90 minutes (i guess 20 minutes extra for those whose native language isnt english). You might wonder why I have not mentioned about going through the admin and user guides for vmware view 5.1 ! but hey after this you might not feel the need of it but if you do then its a great bonus for you.






Monday, September 16, 2013

Browser Optimization for VMware View 5.x for End User Computing Environment

If you are new to this topic then I advice you to please first refer VMware Horizon View Optimization Guide first and then also note that I don't work for mozilla or firefox browser. :)
Following are the view implementations that you want to have on your base image. This Will greatly save on bandwidth of the browser, my estimation is atleast 20% but hey you are the one who will run a benchmark and will let me know the results...
  • Use AdBlock Plus addon and place the icon in the traybar of the firefox in case users want to add some exceptions. Disable non intrusive ads too since adblock accepts payment from bigwigs like google to be added to their non intrusive ad list which appear during search. So on every search you are saving around 20% of the bandwidth used to display that webpage. Use all the following features except typo protection.
    https://adblockplus.org/en/features
  • Use AdBlock Element Hider add on and inform users on how to use it if you can pull this off.
  • Install flashblock add on which will block all the flash on a page and displays an icon instead upon clicking that alone you can make the flash load. It will be useful on almost every site where users visit that site for something else and they care less about the flash ads or animation or promotions on it.
  • Install Black Youtube Theme if your business is into content creation or users need to access youtube some or all the time. It will help their eyes and also since the background is going to be black (only for black color the pixels of a monitor are turned off ) so now the youtube page layout itself will save you atleast 50% of the bandwidth (not the video of course).
  • Leave the default behavior of the firefox to download pdf unchanged rather than opening them in the browser itself since after reading the pdf if the users want to download it then it may have to re download the pdf from the website to the desktop all over again inspite of it being available in the browser already.
    Users may not like their pdfs being downloaded to a directory and then they having to go there to open it everytime. You can circumvent this by making the firefox to open the pdfs in adobe reader when they click on a pdf file.
  • Enable or Disable hardware acceleration in the browser based on your preference. I would disable it by default if the users daily task doesnt involve too much of multimedia task on the web itself. The difference is negligible but still very efficient.
  • Brain-Hack Of Firefox :
    In the address bar "about:config" and enter the world of firefox interiors.
    browser.tabs.animate => False
    network.http.pipelining => True
    network.http.proxy.pipelining => True
    network.http.pipelining.maxrequests => 8
    network.dns.disableIPv6 => True
    content.notify.backoffcount => 5
    config.trim_on_minimize => True
    plugin.expose_full_path => True
    ui.submenuDelay => 0
    javascript.options.jit.chrome => True
    javascript.options.jit.content => True
    browser.download.manager.scanWhenDone => False
    If you are interested to now what all this will do (well as an admin you should be interested to know) then please refer the following.
    http://kb.mozillazine.org/About:config_entries
After going through the article please don't blame if I recommend you to make the firefox as the default browser since it will let you customize in a way that best suits your business or personal needs to give you a most efficient usage of your bandwidth by a browser and if you are using html blast or planning to use, then I must say you should give it a try.
If you think your job is done here, hey there are always areas of improvement and you want to make sure that your users dont get prompts about updates of addons, browser and other configs that you have changed or added. So, please go through https://support.mozilla.org/en-US/kb/how-stop-firefox-automatically-making-connections and trust me it will be worth it. You might want to stop all these updates and want to do it only when you refresh, recompose a desktop and that makes sense too since in cases of persistent desktops the user's addons on his browser might get updated where as the parent VM's firefox addons are still the same and here you might start to see 2 different destinations of bandwidth consumption since adblock ver.x might send a page to the user's desktop with certain ads blocked but the updated adblock add on on the user's desktop might want to block an additional add too.
The best thing would be to install firefox on your desktop/laptop or whatever that you are using and do all these changes and see how it goes with your business applications and sites. If needed make certain changes and when you feel like a king of the firefox customization and configuration or get some confidence then you can implement it in a view environment. Just imagine an IE sending a webpage as it is to the user from your parent VM and a firefox sending the same webpage with ads, trackers, flash blocked (not removed) and all those great about:config optimization; you will definitely save on some bandwidth. You may also look at many other addons to optimize it further like 'no script security suite' which blocks all the untrusted scripts from a webpage. You can preconfigure your parent VM browser addons to exclude your business webapps or other websites which may seem necessary.

Sunday, August 25, 2013

storage latency, performance issues in VMware after changing vcenter license

Issue:- after updating the vcenter server with standard license from evaluation mode, a high latency starts on the storage to vmware.
cause:- when u r in an evaluation mode all the enterprise plus features are applicable for ur environment but when you switch to standard license by entering the std. vcenter license the vmware will start having some issues like latency since the features which u have enabled during the evaluation period may need to be disabled manually especially VAAI.


Thursday, August 22, 2013

windows explorer causes reboot loop

Issue: I have a drive which i use to store movies that i would like to watch later. Whenever i tried to open that particular drive with the windows explorer or any drive which has video files in it the windows use to reboot.
What didnt work: System restore,
uninstallation of  most recently installed application,
driver rollback,
driver update,
display/graphics/nvidia driver update/rollback,
virus scan,
defragmentation etc.,

what worked: enable 'always show icons never thumbnails in folder options>view.
uninstalled codecs from the add/remove programs retaining only the vlc media player and the gom player along with the default windows media player.

Why? : every time i opened a directory with video files windows tried to create a preview using the codes which are installed in the system which was conflicting because gom/vlc/wmp player codecs plus the other codec pack (k-lite mega) pack that i had installed was conflicting/competing with each other to create a preview. In other words windows explorer (explorer.exe was confused about which codec should it use to create a preview of these video files.

Thanks goes to www.sevenforums.com/general-discussion/120827-explorer-exe-restart-loop.html



Tuesday, August 6, 2013

vCenter 5.1 service won't stay started

Issue : vCenter service won't stay started. The server logs off after some time of the reboot.
Resolution: checked the ports on vcenter server with netstat -aon | findstr <port number>
 as per vmware kb and symantec i saw that 80, 443, 8443, 9090 are common for both the vCenter server and symantec end point (SEP). uninstalled the SEP and the vCenter stayed on.

note:next time when you are troubleshooting a vcenter server login or startup issue, after verifying whether all the services are starting, go to add/remove programs of control panel, find what are the ports used/required by the non vmware programs installed in the OS, check other services from start>run>service.msc and see whether the ports are in conflict with the required ports for the vcenter server.

Monday, July 22, 2013

How do I change the vmware network adapter type ?

Sure there are fancy powercli ways to do it,
http://kunaludapi.blogspot.com/2012/09/changing-network-adapter-type-in-vmware.html#.Ue1_Am37aVo
http://psvmware.wordpress.com/2012/11/07/change-vnic-type-from-to-e1000-flexible-vmxnet-enhancedvmxnet-and-vmxnet3-and-unknown-with-set-networkadapter/#more-618
but being a person i am who has stayed away from cli as much as i can i would rather do it the old fashion way through GUI.
Issue: change network adapter type from e1000 to vmxnet3
you may choose to do this when the vm is powered on/off but you will have a disconnectivity of the VM throughout this process.
1. make a note of the ip credentials (ip address, default gateway, subnet mask etc.,) of the network adapters of the VM.
2. vm>vm settings select the network adapter and make a note of the vlan or the portgroup information.
3. select network adapter>click remove>click ok.
4. vm settings> add network adapter and choose vmxnet3>click ok.
5. open console of the VM>assign the ip address to the network adapters in the tcp/ip properties of the nic.
you should now have the same working vm with different network adapter type.

Saturday, July 6, 2013

time lag in the cloned VMs in vmware vsphere 5.x

Issue: The cloned VMs are lagging behind the source VM for 5 minutes.
cloning is currently done via powercli script.
ESXi 5.0.0 build 768111
vCenter server 5.1.0 build 799731
not all but only cloned VMs of a particular vm has this issue.

What didn't work : time synchronization with the host is turned off .
The vms are currently syncing their time with the domain controller.
Vmware tools are up to date.
Sync driver isnt present under Non-Plug and Play Drivers. In device manager.
reinstall vmware tools without the vss (volume shadow copy) and tried cloning  but no go.

the .vmx file had the following entries
tools.syncTime = "0"
If set to TRUE, the clock syncs periodically. 60 sec is by defalut

time.synchronize.continue = "0"
If set to TRUE, the clock syncs after taking a snapshot.

time.synchronize.restore = "0"
If set to TRUE, the clock syncs after reverting to a snapshot.

time.synchronize.resume.disk = "0"
If set to TRUE, the clock syncs after resuming from suspend and after migrating to a new host using the VMware vMotion feature

time.synchronize.shrink = "0"
If set to TRUE, the clock syncs after defragmenting a virtual disk.

time.synchronize.tools.startup = "0"
If set to TRUE, the clock syncs when the tools daemon starts up, normally while the guest operating system is booting

time.synchronize.resume.host = "0"
If set to TRUE, the clock syncs after the host resumes from sleep.

these parameters were defined in the cloned problematic VMs compared to the other working VMs.
This parameters are defined to disable the time synchronization completely see the article
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1189

this means the time sync with the host has been already disabled.

 the polling time was set to 3600sec which is 60 mins in the Domain Controller's registry settings. changed it back to 900 as per VMware and restarted the w32time service

What worked : turning 'sync to the host' on.

VMware boot, SD card, HDD or BFS (Boot from SAN)

There is no doubt that when it comes to reliability, the good old HDD with raid 1 or 5 will be the most reliable since it eliminates the network, switch, storage point of failure then again the server might just boot up fine if network, switch or storage (1 of the raid drive fails ) fails but you will still face the downtime of the VMs which are on a shared drive (assuming that you are using a shared storage for VMs). SD card offers a great alternative for what its worth but then your again SD card might fail (unless you have raid 1 on your SD card too) , the card reader might fail too, in any of these 2 cases your host and VMs are down.
So irrespective of SD, HDD or BFS your VMs will definitely face a downtime if the shared storage and/or the network fails. So, considering that you have already taken care of the switch part by having a redundant switch and your shared storage aka SAN is solid or near fail proof what will be the best option to consider to boot from? SD, HDD or BFS ?!
If you go with the BFS then you don't need internal storage for the servers. Let us consider a HP BL460 and if you have to order a 10 of those you will be saving a lot of money by not ordering any smart arrays with it. You can allcoate 10GB for BFS per server on your SAN. You can also eliminate the need of the physical NICs by using virtual connect or a similar network virtualization. If you take out the need of internal storage and physical NICs on the server, you are almost completely abstracting the VMware from the server hardware. You can even have a backup of the BFS lun of the server just in case you need to boot a different server with it. If you are doing a BFS them make sure you have a syslog server configured for all the hosts to store their log otherwise the BFS partition will be filled sooner than you think with all the logs of the host.

Thursday, June 20, 2013

your VMware vswitch redundancy may not be so failproof

Incident : A host with 4 vmnics has recently lost connection due to a failure in the vmnic. you might be wondering how come all the vmnics failed at the same time ?
Design Flaw : The vswitch0 had 4 vmnic in it vmnicA0,A1,A3,A4 but it still failed because the all these vmnics were not a separate entity but 4 ports of a physical nic. It was a quadport Nic and the firmware on the PCI NIC crashed momentarily, even though it was less than a minute it was still a issue.
Design consideration :
Let us say the host has 2 quad port NICs NIC A & NIC B
make sure any vswitch is made up of nics from both the NICA and NICB.
example:
vswitch0=vmnicA0+vmnicB0
pros: avoid 3 single points of failure
a) failure of a single multi-port PCI (hardware failure) NIC,
b) failure/crashing of the firmware of the multi-port NIC,
c) failure/crashing of the driver of the multi-port NIC.

Wednesday, June 19, 2013

Recreating the vmdk when you can't find the flat-vmdk size

It is a personal note which I wanted to write it down before I forget because I learn it from a friend on phone.
we all know how to recreate vmdk descriptor files but what if the command
ls -l vmdisk0-flat.vmdk
doesnt return any output or gives no size of the flat.vmdk.
well it turns out, you go to the datastore browser>check the size of the flat.vmdk and multiply it with 1024 and it is the same as
ls -l vmdisk0-flat.vmdk.

Intermittent network drop/disconnectivity in VMware environment

It is hard to identify what is wrong or what is going on when your VMs or host has an intermittent network issue. Here is what I have made a note of on my recent encounter with a same problem.
assuming vswitch0 has 2 nics(vmnic0, vmnic1)
start a continous ping to a test VM in the problematic host.
put vmnic0 as active and vmnic1 as unsed and check for network drops.
put vmnic1 as active and vmnic0 as unused and check for network drops.
let us assume on vmnic1 as active there were network packet drops.
assume that
vmnic1 is connected to switchport1
vmnic0 is connected to swtchport0
swap those connections
vmnic1 will now connect to switchport0
vmnic0 will now connect to switchport1
and check whether you are still having the packet drops on the same vmnic1.
If yes then it might be either the cable or the vmnic1 which is faulty.
[You can isolate this by changing the cable with a known good one]
If no, and the packets are now dropping on vmnic0 then it is either the switchport1 or the cable which is faulty.
[You can isolate this by changing the cable with a known good one]

extended scenario:
 If you have 4 vmnics then divide them in a group of 2[groupA=vmnic0,1 GroupB=vmni2,3]
Once you identify on which group you are seeing the packet drop, repeat the process for the vmnic inside the group too.
I mean if the packets are dropping when GroupB is active then keep GroupA and vmnic2 of GroupB as unused and vmnic3 of GroupB as active to check the network drop.
Then redo the same this time with GroupA and vmnic3 of GroupB as unused and vmnic2 of GroupB as active to check the network drop.
If the network drop is on vmnic2 then keep only that as active, othes as unused and then swap the cable and the switch port one at a time to eliminate the possibility of them being faulty.

b4 u do all this make sure that u r up2date on ur drivers/firmware on ur IO devices as per the vmware OS version.

Thursday, June 13, 2013

Why don't I enable HT on my VMware hosts esxi 4.x/5.x



please refer the page 20/54 in the above document and you should see the below documentation.
An ESX system enabled for hyper-threading should behave almost exactly like system without it. Logical
processors on the same core have adjacent CPU numbers, so that CPUs 0 and 1 are on the first core, CPUs
2 and 3 are on the second core, and so on.
You may also refer
and
which is applicable for
·  Product Version(s):
VMware ESX 4.0.x
VMware ESX 4.1.x
VMware ESXi 4.0.x Embedded
VMware ESXi 4.0.x Installable
VMware ESXi 4.1.x Embedded
VMware ESXi 4.1.x Installable
VMware ESXi 5.0.x
So incorrect HT configuration may cause some issues later, hence for a negligible amount or no performance gain by enabling HT we invite the possibilities of the following issues. If they have enabled HT on the physical host then they might have to configure each VM separately so that they can take advantage of the HT, Imagine 20 VMs running on a HT enabled host and we have 5 such hosts in a cluster. We are looking at the reconfiguration of 100 VMs manually.
Configure one virtual machine to use hyper-threading with NUMA, add numa.vcpu.preferHT=TRUE for per-virtual machine advanced configuration file.
Right-click on VM
Select Edit Settings
Click the Options tab.
Highlight General under Advanced options and click Configuration Parameters.
Or enable  it on all VMs
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2003582
So even if they enable HT without manually configuring the VMs the HT is actually not being used and more than 90% of the users are not aware that they have to enable this on VMs too and even if they do, nobody wants to do that on 100 VMs manually for a performance gain which is near 0 (as per vmware documentation). So for a near 0 performance gain we are looking at a possibility of PSOD and if these PSODs are exception 13/14 then that is very hard to isolate, which hardware might have caused it, and almost all the exception 13/14 PSODs that I have seen end up with some or the other hardware replacement, mostly CPU.
Page 18/60
If the hardware and BIOS support hyper-threading, ESX automatically makes use of it. For the best
performance we recommend that you enable hyper-threading, which can be accomplished as follows
however this has only been seen in esxi 5.x and many users that I have dealt with who were running 4.1 haven’t had any considerable performance gain by enabling HT.
So to reiterate again, HT is supported but not advised unless they are (made) aware of all the other cons that they will get in exchange for a negligible performance gain. Some customer’s with database VMs have earlier faced some low performance on their VMs after enabling HT. When we enable Processor resources are shared such as the L2 and L3 caches.  This means that the two threads running on the same processor compete for the same resources if they both have high demand for them.  This can, in turn, degrade performance. Until you have more vCPUs requesting processing power than there are physical cores, HT cannot hurt and provides no value; which means when all the actual physical cores of the CPU are running at near 100% then only the vmware will try to use HT but with DRS enabled on the cluster the VMs will automatically be moved to other hosts reducing the load on the host which means the hosts will practically never reach a state where the CPU is being utilized near 100%. Almost 99% of the VMware hosts that I have seen so far run out of memory first before the cpu usage of the host can actually reach near 90% mark which again makes sure that your host ‘s physical cores are never at above 90% mark because once the memory reaches that 90% mark before the CPU the VMs will be moved to other hosts either by the user or by DRS.
refer
http://communities.vmware.com/docs/DOC-5101
http://vmguy.com/wordpress/index.php/archives/362 
http://serverfault.com/questions/194377/will-disabling-hyperthreading-improve-performance-on-our-sql-server-install
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2008843
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2012404
http://communities.vmware.com/thread/422723?start=0&tstart=0

Thursday, June 6, 2013

(solved) microsoft office installer and Error Code 1303. Set up cannot access the Folder

Scenario: I recently had to uninstall office 2013 because it use to start configure word or outlook whenever I start word or outlook. After hours of wasting time (well it's a Microsoft product, so ....) I uninstalled it and started installing office 2010 which i had earlier but it started giving me errors
After again wasting hours on this in my office the following worked for me.
right click on the following folder
C:\Program Files\Microsoft Office
On the Properties window, select the Security tab
select SYSTEM
click edit
give full permissions and click ok, click ok.
The installation should proceed perfectly.