This SSD caught my eye as a ZIL. I wonder how it compares to my previously benchmarked (a number of times) Kingston SV100 64 GB SSD.
I decided to remove it from the ZIL and try it out. I wanted to make sure I exercise the sequential writes (which is all I really care about in a ZIL–I think) with random data, as some SSD controllers get their speed from compression.
In order to do this test, I first wrote the random data to a memory file system. I then wrote from the memory file system to the SSD.
Poojan@server ~ >!df
df -h -t ufs
Filesystem Size Used Avail Capacity Mounted on
/dev/gpt/usbrootfs 42G 7.4G 31G 19% /
/dev/md0 247M 8.0k 227M 0% /var/tmp
Poojan@server ~ >dd if=/dev/random of=/var/tmp/random bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 1.048121 secs (100043413 bytes/sec)
Poojan@server ~ >dd if=/dev/random of=/var/tmp/random bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 1.048035 secs (100051629 bytes/sec)
Poojan@server ~ >dd if=/var/tmp/random of=/dev/null bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.012362 secs (8482249780 bytes/sec)
Poojan@server ~ >dd if=/var/tmp/random of=/dev/null bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.012305 secs (8521529347 bytes/sec)
Poojan@server ~ >dd if=/var/tmp/random of=/dev/null bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.012351 secs (8489781699 bytes/sec)
Poojan@server ~ >sudo dd if=/var/tmp/random of=/dev/gpt/tank_zil0 bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.641571 secs (163438858 bytes/sec)
Poojan@server ~ >sudo dd if=/var/tmp/random of=/dev/gpt/tank_zil0 bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.641162 secs (163543088 bytes/sec)
Poojan@server ~ >sudo dd if=/var/tmp/random of=/dev/gpt/tank_zil0 bs=1M count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 0.641077 secs (163564741 bytes/sec)
Poojan@server ~ >sudo dd if=/var/tmp/random of=/dev/gpt/tank_zil0 bs=10M count=10
10+0 records in
10+0 records out
104857600 bytes transferred in 0.643163 secs (163034263 bytes/sec)
With random data, we’re seeing around 155 MB/s. This SSD is great for sequential writes.
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