SSD drive with Deduplication (note: NOT SLOG)

[Sasayaki]

Note: To quell preemptive flames, I am stating that the SSD is not a SLOG but an actual storage device, and my box has 32gb of RAM.

Hi all,

I'm considering adding a 120gb SSD to my FreeNAS Mini to run Virtualbox VMs off. Given that this drive is a little small, and all my VMs are the same OS (or one of two OSs), I was considering enabling deduplication and heavy compression on this SSD as a storage volume.

Given that the box has 32gb of RAM, it's an SSD, and the drive is only 120gb which I intend to fill with largely duplicated data, it seems as though this is a good use of this drive.

Thoughts?

 

[cyberjock]

My thoughts are you'll probably be okay with dedup, but realize that dedup does hurt performance. Depending on your CPU it can range from minimal for your situation to crippling. If you are running a Xeon you'll probably be fine. But I probably wouldn't do it with a Pentium.
Keep in mind that just because they are the same OS does not mean that the blocks will end up being the same. So you may see no benefit from using dedup at all depending on how the writes end up aligning.

 

[Ericloewe]

Make sure you test a worst-case scenario before putting that into production, you probably want some guarantee you won't have to hastily move FreeNAS to a machine with 64+GB of RAM.

 

[Sasayaki]

Regarding CPU I'm running an eight-core Atom (FreeNAS Mini).

On reflection, I am considering just buying a new 240gb SSD ($140) and not using dedup at all. It seems simpler and a lot faster.

 

[cyberjock]

Regarding CPU I'm running an eight-core Atom (FreeNAS Mini).

On reflection, I am considering just buying a new 240gb SSD ($140) and not using dedup at all. It seems simpler and a lot faster.

That is probably a much better choice.