Running VM on external drive

[suleyman]

I am tired of running low on disk space on the mac internal hard drive and I was thinking I should just put the VM on an external drive (preferablly firewire). The down side of course will be that I can't just flip the cover of my macbook pro open and start working on a virtual machine, I'd have to plug in the external drive. Worse yet, if it needs external power, I would have to find a power outlet. I did find portable firewire drives powered by a USB cable, which may be a good option (http://www.newegg.com/Product/Product.aspx?Item=N82E16822186191)

I just wanted to ask if anyone made the switch to an external drive and what the performance difference has been? If you have been happy or unhappy about a certain brand external drive, that may also help me and others.

Thank you.

[msaum]

Performance is generally better on an external drive, because you don't have contention with the OS for the same disk.

The down side is you have to lug around an external drive. I just upgraded my internal disk to a 500GB, and use an external when I'm doing disk intensive stuff in a VM.

Try the 7200 RPM 500GB disk by Seagate. You'll get an increase in speed and storage for about $120.

Seagate Momentus 7200.4 ST9500420AS 500GB 7200 RPM 16MB Cache 2.5" SATA 3.0Gb/s Internal Notebook Ha...

[meglet]

I did this for a while, and it worked fairly well. It's been a while, so I don't remember the exact performance difference, but I know the VM was more than useable. I think I used a portable USB drive as I didn't have a portable FireWire drive at the time. I switched back to internal eventually (after upgrading the internal hard drive) because I was tired of carrying around external drives.

Western Digital makes one of their Passport series with a FireWire 800 connection. I have a 500GB passport that ran my iTunes library, and I'm very happy with it. The drive comes with a short FireWire 400 to 800 cable, as well as the standard 800 cable, if your Mac doesn't have FireWire 800.

[Migwuk]

It is faster to use an external drive. Been using one for about 7 years with virtualization software. Firewire 400 or 800 both work well. USB 2.0 also workes but is a little slower. It also allows you to allocate more disk space to the OS. This way you can install more software to test.

[gbullman]

I have always run my VMs on a portable firewire 400 drive (7200 RPM). I can be totally portable by using my machines USB port for power and Firewire for the data connection. I mostly run everything at my desk with the external drive plugged into a powered USB hub. In my case I wanted a drive with an on/off switch so I could leave everything plugged in and shut the drive off at night.

I do think running on an external drive is somewhat faster because the VM is not competing with your Mac for disk access. My belief is one operating system makes pretty frequent access to a disk, having 2 OS make access simultaneously is bound to run into contention.

[suleyman]

Thank you all who responded. I think I will buy the external drive I referred to and use that in the short term. Depending how quickly it gets old to carry around the extra drive, I will upgrade the internal drive. It sounds like the tradoff will be convenience vs performance.

Thanks!

[gbullman]

Those are the interfaces you are looking for. I could not determine from either newegg or iomega's product info if it is a 5400 or 7200 RPM drive inside. I built my own external drive by buying an enclosure and a 7200 RPM drive.

I did some VM copying between drives over the weekend and found that from my external drive to an external FW400 drive I was getting about 25 MB/sec data speeds (from Activity Monitor, about the same for reads and writes). however when copying between external FW400 drives (one connect to machines FW800 port, other to FW400 port) I only got about 17 MB/sec. Given a FW400 drive was involved with both copies I'm guessing the reduced FW to FW data rate was due to contention on the FW bus. I'm guessing that FW800 interface would bump up the sustained transfer rate a bit above the 17 MB/sec I was observing.

[suleyman]

I think another requirement I would have on an external drive besides being firewire would be having no power brick. My initial search on Newegg did not turn up any enclosure that satisfies that requirement. It also seems it will cost more to build my own enclosure than buy one from one of the vendors. I am guessing the iomega drive is 5400 RPM just to reduce the heat generation since the thing does not appear to have any good means to dissipate heat in the first place.

[ehendrix]

Another solution to have your VM on a different drive on your Macbook or Macbook Pro but without the need to carry around a second harddrive is to install a second harddrive in your laptop.

See:

It replaced your SuperDrive with another harddrive and you can still carry around your SuperDrive in case you need it, but how often do you use it?

Just an option.

[msaum]

What a great and simple solution!

This would be great for someone that's running a flash boot drive.

[suleyman]

That is a very cool idea! A little steep on price but a good option. I just got my iomega ego 500 GB drive in the mail now and I am copying the VMs off my internal disk. From what I read here, it will be a good solution for the time being at least.

Thanks

[JDLoft]

I don't have firewire on my netbook so I use the regular USB. USB is better than you may think. My VMs run at a close to native speed. The HDD I use is the Western Digital My Passport Gen. 1. Nice HDD and without the annoying virtual CD with WD software.

[SvenGus]

I posted this question in another discussion, but probably it should have been posted here, first of all...

So, I have recently noticed this very fast - but also quite pricey - flash drive from Kingston:

http://www.kingston.com/datasheets/dthx30_us.pdf

... available in 64, 128 and 256 GB capacities, which, besides being more portable than a traditional external drive, could be a good option to store VMs on for new MacBook Pro and Air users, especially if the internal SSD is not the 512 GB one but with less capacity.

It could probably also be acceptable on an USB 2.0 connection.

The only real question would be: is this kind of modern and evolved USB flash drive finally good for running VMs off it (thus, with a lot of reading and writing, every day, for long periods of time)...?

[ficticio]

I just got the evolution of the Kingston you mean and the VM performance is pretty bad on usb drives, no clue why...