My company builds SDWan network appliances and use SSD's and NVMe's for several key purposes. In order to qualify upcoming new disks for our systems, we typically run 2 hour test runs using fio, for the following: seqrd, seqwr, seqrw, seqrd_seqwr randrd, randwr, randrw, randrd_randwr, randrd_seqwr We've noticed that single disk mode tests (ie seqrd, seqwr, etc) show high numbers than their counter parts in multiple disk mode tests (ie seqrd_seqwr). But we don't understand why. This may part normal, but we don't understand how testing functions to explain this. And if it's not normal, what factors might account for it. I've include a table of test data below. You'll notice, as an example, the seq read and seq write numbers are much high than the seq read part of seqrd_seqwr and even high than seqrw. I've also included a package of fio and test execution files in case that helps. Also prior to each test run, we do a prefill write to the disk and a clearing of the buffer cache, if that helps. FIO SSSTC_CVB-8D120_FW_CZJG801 Seq Read 533MiB/s Seq Write 317MiB/s Seq Read/Write 138MiB/s & 138MiB/s ; why values are lower here? Seq Read, Seq Write 152MiB/s & 152MiB/s ; why values are lower here? Rand Read 532MiB/s Rand Write 253MiB/s Rand Read/Write 129MiB/s & 129MiB/s ; same issue Rand Read, Rand Write 136MiB/s & 136MiB/s ; same issue Rand/Read and Seq/Write 145MiB/s & 145MiB/s ; same issue Any help or info would be appreciated. Tom Gibson mailto:thomas.gibson@xxxxxxx HPE/Aruba HW/SW test engineer Gilroy, CA.
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