X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=e4614ea8675a0c8b2f958ad8c2d6b04e12181939;hb=e231bbe64fffda2090b74941efe21d9c0013cd1e;hp=2403a5cd13048fc27e3a89de406cddbba6560aeb;hpb=de890a1e48d40238dac69f302708dde8719de240;p=fio.git diff --git a/HOWTO b/HOWTO index 2403a5cd..e4614ea8 100644 --- a/HOWTO +++ b/HOWTO @@ -488,6 +488,22 @@ scramble_buffers=bool If refill_buffers is too costly and the target is block compression attempts, but it will stop naive dedupe of blocks. Default: true. +buffer_compress_percentage=int If this is set, then fio will attempt to + provide IO buffer content (on WRITEs) that compress to + the specified level. Fio does this by providing a mix of + random data and zeroes. Note that this is per block size + unit, for file/disk wide compression level that matches + this setting, you'll also want to set refill_buffers. + +buffer_compress_chunk=int See buffer_compress_percentage. This + setting allows fio to manage how big the ranges of random + data and zeroed data is. Without this set, fio will + provide buffer_compress_percentage of blocksize random + data, followed by the remaining zeroed. With this set + to some chunk size smaller than the block size, fio can + alternate random and zeroed data throughout the IO + buffer. + nrfiles=int Number of files to use for this job. Defaults to 1. openfiles=int Number of files to keep open at the same time. Defaults to @@ -627,6 +643,7 @@ iodepth_low=int The low water mark indicating when to start filling direct=bool If value is true, use non-buffered io. This is usually O_DIRECT. Note that ZFS on Solaris doesn't support direct io. + On Windows the synchronous ioengines don't support direct io. buffered=bool If value is true, use buffered io. This is the opposite of the 'direct' option. Defaults to true. @@ -635,6 +652,13 @@ offset=int Start io at the given offset in the file. The data before the given offset will not be touched. This effectively caps the file size at real_size - offset. +offset_increment=int If this is provided, then the real offset becomes + the offset + offset_increment * thread_number, where the + thread number is a counter that starts at 0 and is incremented + for each job. This option is useful if there are several jobs + which are intended to operate on a file in parallel in disjoint + segments, with even spacing between the starting points. + fsync=int If writing to a file, issue a sync of the dirty data for every number of blocks given. For example, if you give 32 as a parameter, fio will sync the file for every 32 @@ -644,7 +668,7 @@ fsync=int If writing to a file, issue a sync of the dirty data fdatasync=int Like fsync= but uses fdatasync() to only sync data and not metadata blocks. - In FreeBSD there is no fdatasync(), this falls back to + In FreeBSD and Windows there is no fdatasync(), this falls back to using fsync() sync_file_range=str:val Use sync_file_range() for every 'val' number of @@ -1101,6 +1125,18 @@ write_lat_log=str Same as write_bw_log, except that this option stores io write_bw_log=str If given, write an IOPS log of the jobs in this job file. See write_bw_log. +write_iops_log=str Same as write_bw_log, but writes IOPS. If no filename is + given with this option, the default filename of + "jobname_type.log" is used. Even if the filename is given, + fio will still append the type of log. + +log_avg_msec=int By default, fio will log an entry in the iops, latency, + or bw log for every IO that completes. When writing to the + disk log, that can quickly grow to a very large size. Setting + this option makes fio average the each log entry over the + specified period of time, reducing the resolution of the log. + Defaults to 0. + lockmem=int Pin down the specified amount of memory with mlock(2). Can potentially be used instead of removing memory or booting with less memory to simulate a smaller amount of memory. @@ -1170,7 +1206,7 @@ gtod_cpu=int Sometimes it's cheaper to dedicate a single thread of uses. Fio will manually clear it from the CPU mask of other jobs. -continue_on_error=bool Normally fio will exit the job on the first observed +continue_on_error=str Normally fio will exit the job on the first observed failure. If this option is set, fio will continue the job when there is a 'non-fatal error' (EIO or EILSEQ) until the runtime is exceeded or the I/O size specified is completed. If this @@ -1179,6 +1215,24 @@ continue_on_error=bool Normally fio will exit the job on the first observed given in the stats is the first error that was hit during the run. + The allowed values are: + + none Exit on any IO or verify errors. + + read Continue on read errors, exit on all others. + + write Continue on write errors, exit on all others. + + io Continue on any IO error, exit on all others. + + verify Continue on verify errors, exit on all others. + + all Continue on all errors. + + 0 Backward-compatible alias for 'none'. + + 1 Backward-compatible alias for 'all'. + cgroup=str Add job to this control group. If it doesn't exist, it will be created. The system must have a mounted cgroup blkio mount point for this to work. If your system doesn't have it @@ -1201,6 +1255,25 @@ uid=int Instead of running as the invoking user, set the user ID to gid=int Set group ID, see uid. +flow_id=int The ID of the flow. If not specified, it defaults to being a + global flow. See flow. + +flow=int Weight in token-based flow control. If this value is used, then + there is a 'flow counter' which is used to regulate the + proportion of activity between two or more jobs. fio attempts + to keep this flow counter near zero. The 'flow' parameter + stands for how much should be added or subtracted to the flow + counter on each iteration of the main I/O loop. That is, if + one job has flow=8 and another job has flow=-1, then there + will be a roughly 1:8 ratio in how much one runs vs the other. + +flow_watermark=int The maximum value that the absolute value of the flow + counter is allowed to reach before the job must wait for a + lower value of the counter. + +flow_sleep=int The period of time, in microseconds, to wait after the flow + watermark has been exceeded before retrying operations + In addition, there are some parameters which are only valid when a specific ioengine is in use. These are used identically to normal parameters, with the caveat that when used on the command line, they must come after the ioengine