X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=4a910a1ac11716d57c3885cf2c2f4fd63f0fa944;hb=a8b412146efdaa79adaa766dd192512bf2178ce7;hp=a534aa865d8c4a9384ebee3d823ecaaaf0fdfb3d;hpb=5d02b083f521bf7508249af8d3c7987992c7b718;p=fio.git diff --git a/HOWTO b/HOWTO index a534aa86..4a910a1a 100644 --- a/HOWTO +++ b/HOWTO @@ -305,6 +305,16 @@ name=str ASCII name of the job. This may be used to override the special purpose of also signaling the start of a new job. +wait_for=str Specifies the name of the already defined job to wait + for. Single waitee name only may be specified. If set, the job + won't be started until all workers of the waitee job are done. + + Wait_for operates on the job name basis, so there are a few + limitations. First, the waitee must be defined prior to the + waiter job (meaning no forward references). Second, if a job + is being referenced as a waitee, it must have a unique name + (no duplicate waitees). + description=str Text description of the job. Doesn't do anything except dump this text description when this job is run. It's not parsed. @@ -767,20 +777,14 @@ ioengine=str Defines how the job issues io to the file. The following 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 + 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. + creates bunch of small files, and engine will + pick a file out of those files based on the + offset enerated by fio backend. Each jobs uses + it's own connection to HDFS. mtd Read, write and erase an MTD character device (e.g., /dev/mtd0). Discards are treated as @@ -1009,7 +1013,9 @@ random_generator=str Fio supports the following engines for generating typically good enough. LFSR only works with single block sizes, not with workloads that use multiple block sizes. If used with such a workload, fio may read or write - some blocks multiple times. + some blocks multiple times. The default value is tausworthe, + unless the required space exceeds 2^32 blocks. If it does, + then tausworthe64 is selected automatically. nice=int Run the job with the given nice value. See man nice(2). @@ -1227,6 +1233,9 @@ exitall When one job finishes, terminate the rest. The default is to wait for each job to finish, sometimes that is not the desired action. +exitall_on_error When one job finishes in error, terminate the rest. The + default is to wait for each job to finish. + bwavgtime=int Average the calculated bandwidth over the given time. Value is specified in milliseconds. @@ -1580,11 +1589,15 @@ log_compression=int If this is set, fio will compress the IO logs as in the specified log file. This feature depends on the availability of zlib. -log_store_compressed=bool If set, and log_compression is also set, - fio will store the log files in a compressed format. They - can be decompressed with fio, using the --inflate-log - command line parameter. The files will be stored with a - .fz suffix. +log_compression_cpus=str Define the set of CPUs that are allowed to + handle online log compression for the IO jobs. This can + provide better isolation between performance sensitive jobs, + and background compression work. + +log_store_compressed=bool If set, fio will store the log files in a + compressed format. They can be decompressed with fio, using + the --inflate-log command line parameter. The files will be + stored with a .fz suffix. block_error_percentiles=bool If set, record errors in trim block-sized units from writes and trims and output a histogram of @@ -1778,11 +1791,13 @@ that defines them is selected. If the job is a TCP listener or UDP reader, the hostname is not used and must be omitted unless it is a valid UDP multicast address. +[libhdfs] namenode=str The host name or IP address of a HDFS cluster namenode to contact. [netsplice] port=int [net] port=int The TCP or UDP port to bind to or connect to. If this is used with numjobs to spawn multiple instances of the same job type, then this will be the starting port number since fio will use a range of ports. +[libhdfs] port=int the listening port of the HFDS cluster namenode. [netsplice] interface=str [net] interface=str The IP address of the network interface used to send or @@ -1841,6 +1856,9 @@ be the starting port number since fio will use a range of ports. [mtd] skip_bad=bool Skip operations against known bad blocks. +[libhdfs] hdfsdirectory libhdfs will create chunk in this HDFS directory +[libhdfs] chunck_size the size of the chunck to use for each file. + 6.0 Interpreting the output ---------------------------