I upgraded my laptop with an Samsung 840 EVO 120GB SSD for programming purposes. I'm going to install Ubuntu Desktop 14.04 LTS on it.

This installation of Ubuntu will get four primary partitions, I'm not going to use any dual boot or something else, just Ubuntu. These partitions will be together 91136 MB, there will be around 15 GB left as "unusable space" because of the four primary partition limit. It will be partitioned on the following way:

Boot: 1024 MB Primary Root: 40960 MB Primary Home: 40960 MB Primary Swap: 8192 MB Primary And some "unusable space" (15 GB)

My question is, will this "unusable space" be automatically available for OP (Over-Provision) on the SSD? Or do I need to have three partitions and some "unallocated space" to get the OP working?

Thank you in advance!

Greetings, Nils


Yes, the unallocated space will be used for routine SSD maintenance such as garbage collection and TRIM during idle times.

The recommended over provision space is 7% to 10% of the SSD drive size. You are likely reserving more than you need to, but there's no harm if you reserve more than the suggested amount. Downside is that you are not fully utilizing available storage.

Source: Page 18, Samsung SSD Magician, User Manual

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Bonus: You should consider 250GB as the performance gains are realized at that size and up and not 120GB.

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  • Thank you for your clear information about OP! I know that it is important for a SSD to have some space left for the SSD Controller. But my question was, will this "unusable space" be automatically used as OP by the SSD? (Because I have already FOUR (max) primary partitions.) – nberlijn Dec 3 '14 at 22:30
  • The 15GB you have unallocated will be used by the SSD controller to optimize the SSD performance (garbage collection and TRIM). – Sun Dec 3 '14 at 23:53

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