Hi FIO users, I am a new user of FIO, and had a few basic questions. I tried to search the existing QA in archives, and have not found an exact answer. Apologies, for the length of the mail and also if this is already addressed (if so, kindly point me to that archive article). Referred to: https://github.com/axboe/fio/issues/163 http://www.spinics.net/lists/fio/msg04104.html http://www.spinics.net/lists/fio/msg03424.html We are trying to do Data Integrity checks using FIO, while performing Sequential & Random Writes/Reads. 1. Basic Write/Read and offline comparison for Data Integrity: a. Is it possible to perform Random Writes to a portion of the disk (using --offset, --size options), and read back from those locations. b. Is it possible to force FIO to access the same LBAs during Writes and Reads, when it is random. c. Is there a way to control the "randomness" using any seeds ? d. Is there a need to use the "state" files ? The intent was to get the data read back to a file, and then compare against expected. 2. FIO comparison using *verify* options: We tried to do an FIO with --do_verify=1 --verify=pattern --verify_pattern=TEST_PATTERN --rw=randwrite (or write - for sequential) In this case, again a few follow-on Questions: a. Does FIO perform writes completely, ie based on --size, or --runtime and then do the read access to verify. What parameters are used (for blk-size, numjobs, qdepth etc.) during the Reads operation. b. is there a way to get the results of the verify step into an output file ? c. The above questions on control of random accesses still exist. d. We tried a run of the above kind, and the FIO run passed, ie there were no obvious errors reported. e. In order to ensure that the verification was correct - we did a 2 step process: [similar to one of the reference articles] FIO#1 - with Writes (--do_verify=0, --verify_pattern=PAT1) FIO#2 - for read/verify (--do_verify=1, --verify_pattern=PAT2) and got some errors.. But, we are not yet sure if that has flagged ALL the locations in error or not. Is there a way to ascertain this ? f. Are there any restrictions in the usage of --num_jobs in such a check.. Regards, - Saju -- 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
