Author Archives: Ranjit Singh Thakurratan

Azure vs AWS IAAS/Networking Comparison

This is a good picture of how AWS and Azure IAAS/networking looks like – the side by side product comparison is really helpful when you are looking at both the products and pulling your hair out.

This again is a high level but begins to draw a picture in your head and helps connect dots.



You can read more @ MSDN – 

Disks Will Fail – VSAN Doesn’t!

I was building my lab with VSAN backed storage – because I did not have a compatible RAID card I grouped the disks as a RAID-0 and presented it to VSAN. It worked and worked well – VSAN saw one big disk of about 1.6 TB (Had three disks worth 550GB each).

I was advised that it was a bad idea – because if the data got striped by the RAID controller and if one disk goes bad – VSAN now is stuck with missing and corrupted disk.

The proper way to do this was to have a RAID-0 on per disk and present all these individual disk volumes to VSAN to participate in a disk group. I went back and did that and boy am I glad that I did.

Today this happened


The fix was easy – Just highlight the disk and click on actions to remove the disk from the disk group. Depending on the failure you might be able to recover the data vsan-fail2

Thanks to Luke Huckaba – @thephuck for pointing it out in my lab which saved me hours of work later.

Now time to setup SPBM to avoid multiple failures 😀

Running Nested ESXi on VSAN

Was trying to deploy a nested ESXi on VSAN backed storage and kept running into this error during install.

This program has encountered an error:

Error (see log for more info):
Could not format a vmfs volume.
Command ‘/usr/sbin/vmkfstools -C vmfs5 -b 1m -S datastore1
/vmfs/devices/disks/mpx.vmhba1:C0:T0:L0:3′ exited with status 1048320

Turns out the problem is with a SCSI-2 reservation being generated as part of creating a default VMFS datastore. You can read more here.

The fix was this simple hack. = run this in each of your hosts and no system reboot is required.

esxcli system settings advanced set -o /VSAN/FakeSCSIReservations -i 1


New NSX Versions

VMware today announced new NSX versions

New NSX Offerings

Standard Edition: Automates IT workflows, bringing agility to the data center network and reducing network operating costs and complexity.

Advanced Edition: Standard Edition plus a fundamentally more secure data center with micro-segmentation. Helps secure the data center to the highest levels, while automating IT provisioning of security.

Enterprise Edition: Advanced Edition plus networking and security across multiple domains. Enables the data center network to extend across multiple sites and connect to high-throughput physical workloads.

See more at:

EMC World – Virtustream Cloud Security and Risk Compliance

EMCWORLD – Getting started with Containers

VCSA DNS Error Troubleshoot

Setup Bind but vCenter appliance couldn’t see it. This is how you troubleshoot that.

To resolve this issue from vCenter:

  1. Open the console to the vCenter Server Appliance and press CTRL+ALT+F3 and log in with root credentials that you mentioned during the install phase.
  2. To enable shell, run this command.

    shell.set –enabled true

  3. Enter shell with this command:


  4. Ping the DNS servers to confirm communication with this command:

    ping yourdnsfqdn

  5. Use nslookup to make sure the vCenter Server Appliance can be resolved:

    nslookup vcenterFQDN

  6. Use the nslookup command to resolve the shortname.
  7. After underlying networking issue is resolved, redeploy the vCenter Server Appliance.

My issue was that firewalld was blocking DNS and once I took it out it worked. Stop yelling I will add the rules once vCenter is installed fully.

It is recommended that once you are able to reach DNS – you should redeploy vCenter.

Hope this helped.

VMware Continuent Tungsten Replicator

I was trying to get a high level overview on the Continuent Tungsten replication and this video was pretty good which helped me understand some of its high level features.

Are you using Continuent – share you experiences!

Preview New Products in Amazon AWS

Two products are in preview mode in AWS. This is a brief post about them.

DMS – DMS stands for database migration services. This service allows you to migrate a source database to a target database by means of a replication instance. AWS also allows you to migrate to a different database by using the AWS schema generator tool to generate a new appropriate schema for the new database. The replication appliances or instances are at the heart of the conversion process where all the conversion takes place. It is available in multiple sizes and depends on your performance requirements.

Below is a list of different sizes of the replication instance available.

Some points to remember.

  1. During conversion source db is fully operational and the process is non disruptive.
  2. Any delta changes at source are also fully replicated to the target. The replication appliance takes care of this and also does compression.
  3. There are no hidden charges – you only pay for the size of replication appliance you deploy regardless of your db size.
  4. Transfer between similar databases or transfer among dissimilar databases.
  5. DMS can also be used as a disaster recovery product because of its ability to constantly replicate the changed data from source to target.

Elastic File System – AWS enters the file storage sector by introducing the elastic file system – a file storage system over NFSv4 protocol. We know that S3 provides object storage and EBS provides block storage for AWS work loads. Now EFS provides file storage allowing for easy consumption for your workloads.

Some points to remember.

  1. EFS has no base charge and is pay as you go at 0.30 cents a GB. You only pay for what you use.
  2. EFS is mounted directly to your EC2 instance and multiple EC2 instances can share a EFS mount.
  3. EFS is backed by SSD storage and there is no additional cost for performance gains.
  4. EFS in theory is advertised as unlimited growth.
  5. Multiple EC2 instances in different Availability zones in a region can access the same EFS instance.
  6. EFS instance is replicated across multiple availability zones.

Hope this gave you a pretty high level over view of what AWS has up and coming.