Hello again, We are interested in making changes to the Seagate branch of FIO that ideally would be widely picked up that would allow FIO to run well on Host Managed/Zoned Block Command (ZBC) drives. Host Managed drives have some simple restrictions which make running workloads on them very challenging. The main hurdles to overcome are all writes must be at its zone write pointer, all reads must be below its zone write pointer, and reads or writes can be over more than one zone. The largest difficulty is to get random performance data. To do this we will need to add the capability to write randomly between zones (but sequentially within zones) and only read what has been written. There seem to be two approaches that could work for this and I'd appreciate any advice as to which approach to pursue. Approach 1: We could let FIO pick I/O offsets as it usually does, but change those offsets into legal ones before they reach the drive. Approach 2: We create a random Host Managed specific workload which will be aware of where it is legal to read and write and will only pick offsets that are valid. Additionally, we would later make some small changes to the existing sequential workloads that would prevent I/O over zone boundaries and do some preparation (writing over zones we are planning to read and resetting the write pointers of zones we want to write over). I am leaning towards this approach because it makes more sense to me. Either way, we will need to implement some way of keeping track of where it is legal to read and write as well as send some new commands like get zone information and reset write pointer(s). Again, it seems like there are two viable approaches. Approach 1: We can create a new I/O engine which handles all the I/O as well as any additional ZBC specific commands like get zone information and resetting write pointers. However, we would like to avoid this option because our customers to use the I/O engine they are comfortable with. Approach 2: We create a layer above the I/O engine which watches all of the I/O and keeps track of the write pointers on the drive as well as issuing any additional ZBC commands as necessary. Thank you, Phillip Chen -- 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
