Solidigm

GLi29 · ‎09-02-2019

Random write to Intel SSDPEDKE040T7.

After 1.4TB random write, SSD write performance drops to half.

The test script :

#!/bin/sh
 
nvme="$1"
if [ -z "$nvme" ]; then
    echo "Usage $0 <nvme>"
    exit 1
fi
 
ls "$nvme" || exit 1
 
size_k=$(grep $(basename $nvme) /proc/partitions | awk '{print $3}')
 
echo "$nvme: size_k $size_k"
 
size_128k=$(($size_k / 128))
len_128k=$((4096+1))
 
while :; do
    pos=$(perl -e '{print int(rand()*('$size_128k'-'$len_128k')) . "\n"}')
    pos=$((pos - pos % 4096))
    echo -n "$pos: "
    /data/misc/dd if=/dev/zero bs=128k count=$len_128k of=$nvme oflag=direct seek=$pos 2>&1 | grep copied 
done

The attach is its output.

The output shows the write performance drops from 1.9 GB/s to 1.0 GB/s and stay in 1.0GB/s.

A sequential dd all SSD brings the performance back.

Can you explain what causes it?

Can you can provide a spec to explain it?

Best regards,

Guofeng

Santiago_A_Inte · ‎09-18-2019

Hi GLi29;

Greetings from Intel® SSD communities.

This is a friendly reminder this topic remains open, awaiting for your reply.

Please let us know if there’s anything else we can help you with.

We will be available to help you in any way we can.

Have a nice day

Santiago A.

Intel® Customer Support Technician

A Contingent Worker at Intel

Santiago_A_Inte · ‎09-24-2019

Hi GLi29;

Greetings from Intel® SSD communities.

This is to let you know, this topic is being closed.

Please feel free to get back to Intel® communities, whenever you might feel necessary.

Have a nice day,

Santiago A.

Intel® Customer Support Technician

A Contingent Worker at Intel

Solidigm

Random write causes SSD write performance drop