On 01/05/2018 11:56 AM, Javier Gonzalez wrote: >> On 5 Jan 2018, at 20.53, Matias Bjørling <m@xxxxxxxxxxx> wrote: >> >> On 01/05/2018 08:52 PM, Javier Gonzalez wrote: >>>> On 5 Jan 2018, at 20.33, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: >>>> >>>> On 01/05/2018 05:16 AM, Matias Bjørling wrote: >>>>> From: Javier González <javier@xxxxxxxxxxxx> >>>>> >>>>> 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 >>>> >>>>> +#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. >> >> I think what Randy means is, why is the value not 20% or 7%, which is the traditional over-provisioning on SSDs. > > We decided 11% based on customer input, but 7% and 20% are also good > default values. I'm ok with having any of those as default - anyone > caring about OP will define the value on target creation, which is the > primary objective of this patch. Got it. Thanks. -- ~Randy
