On Thu, Mar 07 2013, Gavin Martin wrote: > Does Fio know the MaxLBA for devices it runs to? If the size variable > has a percentage value, for example 50%, then it must have to read the > MaxLBA to know that on a 4TB drive the size of file we want is 2TB? > Is this correct or does it use another method? That is correct, when adding files or devices, fio will check and store the size of them. > If so would it be possible to have a reserved keyword for the MaxLBA, > much as you do currently for pagesize, memory & cpu's so that the size > & offset variable could make use of it, with the simple math > supported? The problem here is that the current keywords are system wide specific, whereas MaxLBA could refer to any particular device. So it would only be valid within the scope of a single file. > Not being a programmer and having very limited knowledge when it comes > to reading code, I have no idea if this is even possible within Fio? > > If the above is not suitable, would it be possible for the offset > variable to accept percentages much like the size variable? > > This comes from wanting to run Fio from dual hosts, I need to be able > to control which parts of the disk each host can access, so that they > do not interfere, on drives & ssds of many different sizes. > > Basic example: > > [Host 1] > size=50% > offset=0 > > [Host 2] > size=50% > offset 50% Suppporting a percentage with offset would not be hard, but it would only really work for a single file. For that, it would be doable. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
