fio基础11

rdma The RDMA I/O engine supports both RDMA memory semantics (RDMA_WRITE/RDMA_READ) and channel semantics (Send/Recv) for the InfiniBand, RoCE and iWARP protocols. falloc IO engine that does regular fallocate to simulate data transfer as fio ioengine. DDIR_READ does fallocate(,mode = keep_size,) DDIR_WRITE does fallocate(,mode = 0) DDIR_TRIM does fallocate(,mode = punch_hole) e4defrag IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment activity in request to DDIR_WRITE event rbd IO engine supporting direct access to Ceph Rados Block Devices (RBD) via librbd without the need to use the kernel rbd driver. This ioengine defines engine specific options. gfapi Using Glusterfs libgfapi sync interface to direct access to Glusterfs volumes without options. gfapi_async Using Glusterfs libgfapi async interface to direct access to Glusterfs volumes without having to go through FUSE. This ioengine defines engine specific options. libhdfs Read and write through Hadoop (HDFS). The 'filename' option is used to specify host, port of the hdfs name-node to connect. This engine interprets offsets a little differently. In HDFS, files once created cannot be modified. So random writes are not possible. To imitate this, libhdfs engine expects bunch of small files to be created over HDFS, and engine will randomly pick a file out of those files based on the offset generated by fio backend. (see the example job file to create such files, use rw=write option). Please note, you might want to set necessary environment variables to work with hdfs/libhdfs properly. mtd Read, write and erase an MTD character device (e.g., /dev/mtd0). Discards are treated as erases. Depending on the underlying device type, the I/O may have to go in a certain pattern, e.g., on NAND, writing sequentially to erase blocks and discarding before overwriting. The writetrim mode works well for this constraint. external Prefix to specify loading an external IO engine object file. Append the engine filename, eg ioengine=external:/tmp/foo.o to load ioengine foo.o in /tmp. iodepth=int This defines how many io units to keep in flight against the file. The default is 1 for each file defined in this job, can be overridden with a larger value for higher concurrency. Note that increasing iodepth beyond 1 will not affect synchronous ioengines (except for small degress when verify_async is in use). Even async engines may impose OS restrictions causing the desired depth not to be achieved. This may happen on Linux when using libaio and not setting direct=1, since buffered IO is not async on that OS. Keep an eye on the IO depth distribution in the fio output to verify that the achieved depth is as expected. Default: 1. iodepth_batch_submit=int iodepth_batch=int This defines how many pieces of IO to submit at once. It defaults to 1 which means that we submit each IO as soon as it is available, but can be raised to submit bigger batches of IO at the time. If it is set to 0 the iodepth value will be used. iodepth_batch_complete_min=int iodepth_batch_complete=int This defines how many pieces of IO to retrieve at once. It defaults to 1 which means that we'llaskforaminimumof1IOintheretrievalprocessfromthekernel.TheIOretrievalwillgoonuntilwehitthelimitsetbyiodepth_low.Ifthisvariableissetto0,thenfiowillalwayscheckforcompletedeventsbeforequeuingmoreIO.ThishelpsreduceIOlatency,atthecostofmoreretrievalsystemcalls.iodepth_batch_complete_max=intThisdefinesmaximumpiecesofIOtoretrieveatonce.Thisvariableshouldbeusedalongwithiodepth_batch_complete_min=intvariable,specifyingtherangeofminandmaxamountofIOwhichshouldberetrieved.Bydefaultitisequaltoiodepth_batch_complete_minvalue.