On 5 Jan 2018, at 20.33, Randy Dunlap [off-list ref] wrote:

On 01/05/2018 05:16 AM, Matias Bjørling wrote:

quoted

From: Javier González <redacted>

Allow to set the over-provision percentage on target creation. In case
that the value is not provided, fall back to the default value set by
the target.

In pblk, set the default OP to 11% of the total size of the device

quoted

+#define PBLK_DEFAULT_OP (11)

Hi,
Just curious -- where does 11 come from?  Is it a spec value?

11 stands for 11% over-provisioning for the media to allow garbage
collection. Different SSDs have different values based on the targeted
workload - 11% is a common default value for standard drives.

The spec. does not specify any default values of over-provisioning.

Javier.