Intel DC P3600 SSD random vs sequential reads performance difference

[IS2]

Hello,

I am testing Intel DC P3600 SSD on Linux (kernel 4.9) with fio-2.16.

I am running performance tests using sync ioengine with 4K blocksize, direct

access and queue depth of 1. Below is the fio config file:

[global]

iodepth=1

direct=1

ioengine=sync

group_reporting

time_based

blocksize=4k

[job1]

rw=randread

;rw=read

filename=/dev/nvme0n1

name=raw=sequential-read

numjobs=1

runtime=60

I see a huge performance difference between sequential and random read workload:

sync sequential: 75K IOPS

sync random: 10K IOPS

Using other synchronous ioengines situation is the same:

pvsync sequential: 75K IOPS

pvsync random: 10K IOPS

pvsync2 sequential: 75K IOPS

pvsync2 random: 10K IOPS

Why the difference is so huge? What makes sequential much faster than random?

[idata]

Hello NFN,

According to our database, these are the SSDs associated with the model numbers that you provided:• SSDPE2ME800G4D (OEM drive): Intel® SSD DC P3600 Series (800GB, 2.5in PCIe 3.0, 20nm, MLC)• SSDPE2MD800G4: Intel® SSD DC P3700 Series (800GB, 2.5in PCIe 3.0, 20nm, MLC) Both SSDs are part of the Drive Data Center Family for PCIe*, and they were launched at the same time. The DC P3700 should have better performance than the DC P3600, but I cannot provide further insight since one of the drives you are comparing is an OEM drive. OEMs usually install custom firmware in order to adapt the drive to their customer's needs. The firmware is an important variable that limits the scope of my support in this matter.Regards,Andres V.