Virtualizing on SSD pros and cons

I'm planning to virtualize Kubuntu on my laptop and I'm thinking about placing the installation on the SSD rather than the HDD. I wanted to get a sense of the pros and cons before I do, though.

Here's what my understanding is:

Pros:
Runs fast - I'll probably be 50/50 on host and guest so this is a big pro for me

Cons:
More ssd space taken up - currently I'm using 48.7 GiB on a 128 GB m4 ssd, so an extra 20 GB isn't a big deal
No TRIM???
More writes to ssd - don't really care
Might slow down performance - don't really care if it's less than 25% difference


Anything else I'm missing?

 

I don't see why TRIM wouldn't work when using virtual machines. IIRC, a virtual machine is just another file on the host OS, and thus is treated the same as all other files on the disk and is taken care of with TIRM from the host OS.

And the only way I see this slowing down performance is if your SSD is just about completely full, but otherwise a virtual machine is just another file and the VM software just another program.

All that said, I've never noticed any unusual activity or performance decrease on my laptop simply by using a virtual machine.

 

TRIM only works on the actual deletion of files. Within a VM, usually everything exists in disk files which either grows / shrinks with VM usage, but is never deleted. So TRIM would ineffective in that use case.

TBH, I've never noticed that my VM's disk files ever "decrease" in size. So if they're always growing, then TRIM wouldn't matter in that case. My guess is that when one runs the VM software "defragger" on the disk (not within the Guest OS), I bet it would then shrink the file.

 

PerfectDisk 12.5 VMware Workstation can do this.

See:
VMware Workstation Defrag - PerfectDisk 12 VMware Workstation



Along with other Virtualization Optimization options:

See:
PerfectDisk Business Defrag, RAM Disk, File Recovery | Raxco Software

 

Actually.... VirtualBox does this too (they just updated) as far as I recall

 

Only con really is diskspace, I try very hard hard to keep my VMs under 80 gigs which means cleaning and reverting to a base snapshot every few months or so.

a few years back there were concerns with vm's writing a lot on an ssd (when hitting too much writes could "wear out your ssd faster" was still the trend, since every pause, sleep,hibernate,shutdown,copy has write transactions to the host), nowadays nobody really cares anymore.