X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=ee899b8fdb6c402814086dde41f986d152c456c9;hp=0ef7ca42120d175c3115207861f50b964a07958e;hb=a596f047e2b3d447ccca76bd075f05473a1f8d1c;hpb=38dad62d5154ffaad445bd0231b271b9a46a5190 diff --git a/HOWTO b/HOWTO index 0ef7ca42..ee899b8f 100644 --- a/HOWTO +++ b/HOWTO @@ -271,12 +271,14 @@ filename=str Fio normally makes up a filename based on the job name, can specify a number of files by separating the names with a ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb as the two working files, you would use - filename=/dev/sda:/dev/sdb. If the wanted filename does need to - include a colon, then escape that with a '\' character. For - instance, if the filename is "/dev/dsk/foo@3,0:c", then you would - use filename="/dev/dsk/foo@3,0\:c". '-' is a reserved name, - meaning stdin or stdout. Which of the two depends on the read/write - direction set. + filename=/dev/sda:/dev/sdb. On Windows, disk devices are accessed + as \\.\PhysicalDrive0 for the first device, \\.\PhysicalDrive1 + for the second etc. If the wanted filename does need to + include a colon, then escape that with a '\' character. + For instance, if the filename is "/dev/dsk/foo@3,0:c", + then you would use filename="/dev/dsk/foo@3,0\:c". + '-' is a reserved name, meaning stdin or stdout. Which of the + two depends on the read/write direction set. opendir=str Tell fio to recursively add any file it can find in this directory and down the file system tree. @@ -346,10 +348,25 @@ kb_base=int The base unit for a kilobyte. The defacto base is 2^10, 1024. randrepeat=bool For random IO workloads, seed the generator in a predictable way so that results are repeatable across repetitions. -fallocate=bool By default, fio will use fallocate() to advise the system - of the size of the file we are going to write. This can be - turned off with fallocate=0. May not be available on all - supported platforms. +use_os_rand=bool Fio can either use the random generator supplied by the OS + to generator random offsets, or it can use it's own internal + generator (based on Tausworthe). Default is to use the + internal generator, which is often of better quality and + faster. + +fallocate=str Whether pre-allocation is performed when laying down files. + Accepted values are: + + none Do not pre-allocate space + posix Pre-allocate via posix_fallocate() + keep Pre-allocate via fallocate() with + FALLOC_FL_KEEP_SIZE set + 0 Backward-compatible alias for 'none' + 1 Backward-compatible alias for 'posix' + + May not be available on all supported platforms. 'keep' is only + available on Linux.If using ZFS on Solaris this must be set to + 'none' because ZFS doesn't support it. Default: 'posix'. fadvise_hint=bool By default, fio will use fadvise() to advise the kernel on what IO patterns it is likely to issue. Sometimes you @@ -372,10 +389,15 @@ filesize=int Individual file sizes. May be a range, in which case fio and limited to 'size' in total (if that is given). If not given, each created file is the same size. -fill_device=bool Sets size to something really large and waits for ENOSPC (no +fill_device=bool +fill_fs=bool Sets size to something really large and waits for ENOSPC (no space left on device) as the terminating condition. Only makes sense with sequential write. For a read workload, the mount - point will be filled first then IO started on the result. + point will be filled first then IO started on the result. This + option doesn't make sense if operating on a raw device node, + since the size of that is already known by the file system. + Additionally, writing beyond end-of-device will not return + ENOSPC there. blocksize=int bs=int The block size used for the io units. Defaults to 4k. Values @@ -492,6 +514,8 @@ ioengine=str Defines how the job issues io to the file. The following solarisaio Solaris native asynchronous io. + windowsaio Windows native asynchronous io. + mmap File is memory mapped and data copied to/from using memcpy(3). @@ -549,7 +573,14 @@ ioengine=str Defines how the job issues io to the file. The following 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. + 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. @@ -574,7 +605,7 @@ iodepth_low=int The low water mark indicating when to start filling the depth drain down to 4 before starting to fill it again. direct=bool If value is true, use non-buffered io. This is usually - O_DIRECT. + O_DIRECT. Note that ZFS on Solaris doesn't support direct io. buffered=bool If value is true, use buffered io. This is the opposite of the 'direct' option. Defaults to true. @@ -914,6 +945,11 @@ verify_fatal=bool Normally fio will keep checking the entire contents option is set, fio will exit the job on the first observed failure. +verify_dump=bool If set, dump the contents of both the original data + block and the data block we read off disk to files. This + allows later analysis to inspect just what kind of data + corruption occurred. On by default. + verify_async=int Fio will normally verify IO inline from the submitting thread. This option takes an integer describing how many async offload threads to create for IO verification instead, @@ -935,13 +971,18 @@ verify_backlog=int Fio will normally verify the written contents of a associated with an IO block in memory, so for large verify workloads, quite a bit of memory would be used up holding this meta data. If this option is enabled, fio + will write only N blocks before verifying these blocks. + will verify the previously written blocks before continuing to write new ones. verify_backlog_batch=int Control how many blocks fio will verify if verify_backlog is set. If not set, will default to the value of verify_backlog (meaning the entire queue - is read back and verified). + is read back and verified). If verify_backlog_batch is + less than verify_backlog then not all blocks will be verified, + if verify_backlog_batch is larger than verify_backlog, some + blocks will be verified more than once. stonewall Wait for preceeding jobs in the job file to exit, before starting this one. Can be used to insert serialization @@ -976,7 +1017,8 @@ zoneskip=int Skip the specified number of bytes when zonesize data has io on zones of a file. write_iolog=str Write the issued io patterns to the specified file. See - read_iolog. + read_iolog. Specify a separate file for each job, otherwise + the iologs will be interspersed and the file may be corrupt. read_iolog=str Open an iolog with the specified file name and replay the io patterns it contains. This can be used to store a @@ -986,6 +1028,31 @@ read_iolog=str Open an iolog with the specified file name and replay the for how to capture such logging data. For blktrace replay, the file needs to be turned into a blkparse binary data file first (blkparse -o /dev/null -d file_for_fio.bin). + +replay_no_stall=int When replaying I/O with read_iolog the default behavior + is to attempt to respect the time stamps within the log and + replay them with the appropriate delay between IOPS. By + setting this variable fio will not respect the timestamps and + attempt to replay them as fast as possible while still + respecting ordering. The result is the same I/O pattern to a + given device, but different timings. + +replay_redirect=str While replaying I/O patterns using read_iolog the + default behavior is to replay the IOPS onto the major/minor + device that each IOP was recorded from. This is sometimes + undesireable because on a different machine those major/minor + numbers can map to a different device. Changing hardware on + the same system can also result in a different major/minor + mapping. Replay_redirect causes all IOPS to be replayed onto + the single specified device regardless of the device it was + recorded from. i.e. replay_redirect=/dev/sdc would cause all + IO in the blktrace to be replayed onto /dev/sdc. This means + multiple devices will be replayed onto a single, if the trace + contains multiple devices. If you want multiple devices to be + replayed concurrently to multiple redirected devices you must + blkparse your trace into separate traces and replay them with + independent fio invocations. Unfortuantely this also breaks + the strict time ordering between multiple device accesses. write_bw_log=str If given, write a bandwidth log of the jobs in this job file. Can be used to store data of the bandwidth of the @@ -1231,8 +1298,10 @@ For scripted usage where you typically want to generate tables or graphs of the results, fio can output the results in a semicolon separated format. The format is one long line of values, such as: -2; client1;0;0;1906777;1090804;1790;0;0;0.000000;0.000000;0;0;0.000000;0.000000;929380;1152890;25.510151%;1078276.333333;128948.113404;0;0;0;0;0;0.000000;0.000000;0;0;0.000000;0.000000;0;0;0.000000%;0.000000;0.000000;100.000000%;0.000000%;324;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%;0.0%;100.0%;0.0%;0.0%;0.0%;0.0%;0.0% -;0.0%;0.0%;0.0%;0.0%;0.0% +2;card0;0;0;7139336;121836;60004;1;10109;27.932460;116.933948;220;126861;3495.446807;1085.368601;226;126864;3523.635629;1089.012448;24063;99944;50.275485%;59818.274627;5540.657370;7155060;122104;60004;1;8338;29.086342;117.839068;388;128077;5032.488518;1234.785715;391;128085;5061.839412;1236.909129;23436;100928;50.287926%;59964.832030;5644.844189;14.595833%;19.394167%;123706;0;7313;0.1%;0.1%;0.1%;0.1%;0.1%;0.1%;100.0%;0.00%;0.00%;0.00%;0.00%;0.00%;0.00%;0.01%;0.02%;0.05%;0.16%;6.04%;40.40%;52.68%;0.64%;0.01%;0.00%;0.01%;0.00%;0.00%;0.00%;0.00%;0.00% +A description of this job goes here. + +The job description (if provided) follows on a second line. To enable terse output, use the --minimal command line option. The first value is the version of the terse output format. If the output has to @@ -1256,6 +1325,8 @@ Split up, the format is as follows: Bw: min, max, aggregate percentage of total, mean, deviation CPU usage: user, system, context switches, major faults, minor faults IO depths: <=1, 2, 4, 8, 16, 32, >=64 - IO latencies: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000 - Text description - + IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000 + IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000 + Additional Info (dependant on continue_on_error, default off): total # errors, first error code + + Additional Info (dependant on description being set): Text description