SSD performance numbers

[Stephen J]

So I thought I would share some numbers on SSD performance. I replaced a 4 disk pool in my 16bay freenas server with Corsair ForceGT 180G SSDs. This is my VM storage. I ran a dd test as described in the Benchmarking sticky. Here are my results:

Write:
dd if=/dev/zero of=/mnt/SSD/tmp.dd bs=2048k count=50k
107374182400 bytes transferred in 125.811774 secs (853450985 bytes/sec) 813MB/s

Read:
dd if=/mnt/SSD/tmp.dd of=/dev/null bs=2048k count=50k
107374182400 bytes transferred in 51.752571 secs (2074760347 bytes/sec) 1.9322GB/s


Just to see how much difference it made, I striped all 4 of them. This shows how efficiently ZFS treats mirrors like stripes.

Write:
dd if=/dev/zero of=/mnt/SSD/tmp.dd bs=2048k count=50k
107374182400 bytes transferred in 109.587707 secs (979801344 bytes/sec) 934MB/s

Read:
dd if=/mnt/SSD/tmp.dd of=/dev/null bs=2048k count=50k
107374182400 bytes transferred in 51.732187 secs (2075577867 bytes/sec) 1.9330GB/s

And as a Raid-Z2

dd if=/dev/zero of=/mnt/SSD/tmp.dd bs=2048k count=50k
107374182400 bytes transferred in 178.002746 secs (603216438 bytes/sec) 575MB/s

dd if=/mnt/SSD/tmp.dd of=/dev/null bs=2048k count=50k
107374182400 bytes transferred in 82.478389 secs (1301846261 bytes/sec) 1.21GB/s


One thing that suprised me and I thought was interesting, SSDs don't provide drive activity info to the drive lights. Those four bays are just dark.

Stephen

 

[Joshua Parker Ruehlig]

2GB/s read 0.9GB/s write, wow!

 

[StephenFry]

Stephen J, thank you for posting this. Very interesting.

And indeed, wow!

 

[Stephen J]

and with RAID Z1

Write:
dd if=/dev/zero of=/mnt/ssd/readwritetest/tmp.dd bs=2048k count=50k
107374182400 bytes transferred in 115.681468 secs (928188276 bytes/sec) 885MB/s

dd if=/mnt/ssd/readwritetest/tmp.dd of=/dev/null bs=2048k count=50k
107374182400 bytes transferred in 73.210526 secs (1466649515 bytes/sec) 1.36GB/s

Stephen