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How To Enable SSH on VMware ESXi 5 / 5.5 / 6 & All Other Versions

Many necessary administrative functions on ESXi requires SSH access. For example, offline bundles, third party management utilities, backup utilities, and many other tasks require you to log in to the ESXi console, via SSH or physically. This post will guide you through the process of enabling the SSH service, and opening up the firewall to allow access. This process works on all versions of ESXi, including the newer versions such as 5, 5.5, and 6. Lets get started.

Enabling SSH on an ESXi host

There are two steps involved in getting SSH access set up on an ESXi host.

  • Enabling the SSH service
  • Opening port 22 (SSH port) on the firewall

First, log into the VMware vSphere Client. You can login directory to the host, or to a vSphere server, it doesn’t matter. Select the host in the left panel, then navigate to Configuration > Security Profile, once you are there, click on the Properties option to the right of Services.

Screen-Shot-2015-05-19-at-11.31.26-AM

Now, select SSH, then Options.

Screen Shot 2015-05-19 at 11.34.29 AM

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Simple Method to Benchmark Disk Read & Write Speeds From the Linux Command Line

Recently, I’ve been exploring high availability iSCSI targets and using them as virtual machine storage. I have always been a bit weary of iSCSI performance over gigabit networks due to some not-so-great experiences many years ago. iSCSI technology has progressed quite a bit since then. FreeNAS has an excellent implementation of iSCSI, as well as Nexenta. I wanted to get a good grasp on how well everything was performing, so I decided to run some basic benchmarks.

The virtual machine I’m working with has Ubuntu 15.04 installed, but these commands will work on just about any linux distribution in existence. The hyperviser is running VMware ESXi 6, with this particular virtual machine stored on an iSCSI target served from a FreeNAS virtual machine running on another VMware ESXi hyperviser. The FreeNAS virtual machine has been given PCI Passthrough to a 3ware 9650SE-16ML, connected to 4x1TB Hitachi SATA Hard Drives exported as JBOD (individual drives, no RAID). FreeNAS configured a RAID10 with the four drives, which is where the iSCSI target resides. The network is gigabit, with an Adtran NetVanta 1524ST switch. I have not enabled Jumbo Frames. The theoretical maximum transfer speed on a gigabit network is about 125MB/s. Of course, with the overhead associated with TCP/IP and iSCSI encapsulation, a single link should be a little less. Lets get started.

To test WRITE speed of hard disk using the DD command:

#  sync; dd if=/dev/zero of=tempfile bs=1M count=1024; sync
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 10.8496 s, 99.0 MB/s

So, this command writes a bunch of zeros to a file called tempfile, with a size of 1024MB. If you want to use a larger test file, you can change “1024” to a higher number. For instance, changing 1024 to 10000 would write a 10GB temp file. This command only tests the write speed. As you can see, the reported write speed was 99MB/s, not too shabby.

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