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Re: compare dd to hdparm read perf on nvme SSD



On 2022-08-29 07:23, Rick Leir wrote:
What is your block size parameter?
$ dd bs=100000 if=aaa of=bbb
Whatever the default was.


Block size makes a big difference to performance.
I should have used hdparm -tT on the old drive.I should have used hdparm -tT on the old drive.

Except maybe fio is better.
It is different and it says the nvme is slower.

The specs say 3000+MB/s which is quite a bit more than the 900 I get.

$ sudo fio --filename=/dev/nvme0n1 --direct=1 --rw=randread --bs=64k --ioengine=libaio --iodepth=64 --runtime=120 --numjobs=4 --time_based --group_reporting --name=throughput-test-job --eta-newline=1 --readonly throughput-test-job: (g=0): rw=randread, bs=(R) 64.0KiB-64.0KiB, (W) 64.0KiB-64.0KiB, (T) 64.0KiB-64.0KiB, ioengine=libaio, iodepth

Run status group 0 (all jobs):
   READ: bw=860MiB/s (902MB/s), 860MiB/s-860MiB/s (902MB/s-902MB/s), io=101GiB (108GB), run=120018-120018msec

Maybe I need a PCI6 motherboard. :-)

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