External SSD Running VMs

External SSD Running VMs

I’ve found it a life saver when I could use fast external drives to run virtual. That’s super helpful when your virtual lab starts to eat up local drive space. Just beware in trying to run it on a random thumb drive. Running on something like this external drives could lead in performance loss. But that doesn’t have to be the entire case. Especially when you choose drives like SSDs over HDDs.

How is the performance of running virtual machines from an external SSD? Running virtual machines from an external SSD can diminish input lag you would get from lower grade HDD. The most common solutions an external SSD provides is space for the local drive; and a noticeable performance enhancements.

You’ll be able to solve the space issue when you opt for an external SSD. The next issue that’s hardly thought of is performance. An SSD is a good opt over HDD but there is more to consider.

Choosing the SSD

Running virtual machines from an external SSD can help the local drive from multiple standpoints. One being that the storage is off set. The second being is the performance over an external HDD.

Many external drives are chosen usually for normal cold storage purposes. This means that items from the local drive are backed up to another drive or used to transfer files from one machine to another. With virtual machines, there are other considerations to be made especially when running them on an external drive.

There are three factors that determine the performance of running virtual machines off an external drive: traffic throughput from the external drive to the motherboard; the storage space required for the virtual machines; and finally the read and write speeds of the external drive.

It’s easy to fill up your local drive if you’re running a hardcore virtual lab.

I know this has been my case with running a pFsense router, several Windows and OS machines, and enterprise-like servers.

Traffic throughput is usually determined by the USB port speeds the external drive is capable of. You can run virtual machines with a throughput base of USB 1.0 or 2.0, however USB 3.0 will outperform the previous two by a significant margin. It’s always recommended that you run your virtual machine from a through put of USB 3.0. Especially when you’re configuring the virtual machine – I’ll explain more about how some slower performance drives maybe okay for what you need to do.

The next factor is storage space. This is usually the only checkbox that people tick when looking for an external drive to store their media. It’s a simple checkbox. How much space will you need to store your data, in this case your virtual machine.

Let’s say you run around the close minimum for a regular Windows 10 virtual machine of 20 GB. You can basically fit 50 of these in a 1 TB hard drive. That maybe too much depending on what you need. But if you decide to use it for storage apart from your virtual machines, why not go for it.

Finally, the factor of read and write speeds will make or break running your virtual machines off an external drive. To keep it simple you’ll want a 7200 RPM + on an HDD, but this is more of an outdated recommendation compared to the SSD. For SDD, the fast performers will have read and write speeds of 500 MB/s.

You’ll be fine when running virtual machines off an SSD using the above recommendations. If you’ve ran VMs off normal external drives before, you will notice a huge difference when upgrading read and write speeds.

The only time you maybe okay with running virtual machines off a regular SSD that do not fit the above criteria will be when you just need to spin up a virtual machine for minimal background information. Such as small traffic data that gets queried less for other virtual machines. But for the most part a high performance SSD will save time in configuring normal virtual machines.

SSD Recommendations

A one stop shop that fist the above criteria for excellent performance would be to with this external SSD. Because the drive is meant to fit with an enclosed motherboard, it will need an external enclosure. This will allow you to connect this drive to an external USB port. It is a bit heftier on the price, but if considered an investment this will be a huge value add. It’s 1 TB of fast read and write speeds for solid state as well as fast bus speeds compatible up to 3.0 USB drives. Good luck filling this drive up with your VMs.

For the budget friendly, without compromising performance I would look into this. The biggest difference here versus the one directly above is that the storage is 250 GB. You can do a lot with that. If you don’t plan on scaling your lab environment much more than that, this would be a good purchase.

There are plenty other external SSDs that can be used for high performance. Just remember, when shopping around, the three main criteria needs to be checked:

  1. Storage space
  2. Traffic throughput
  3. Read/write speeds. 

Related Questions

How many VMs can fit on an SSD?

This entirely depends on the lab environment you’re building. Let’s say you have a minimal Windows 10 image running. This is about 20 GB, so you’d need to have 50 instances of these in order to fill a 1 TB SDD. 

However, some images may vary. Others could run Linux, which is more compact in terms of storage than the Windows 10 counterpart; and others may require a higher storage capacity – running database servers, etc.

There is also the question of scale and spinning up the same VM environment. For instance you may have one lab you need to shutdown and bring another one up.

With a large SDD storage capacity, you won’t need to delete previous labs. It’s safe to say that a 1 TB drive will help you run maybe 50 VMs if you’re running lite Windows 10 version. This may seem a lot at first. But as mentioned, the more labs are spun and set a side for future use will quickly fill up this space.

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