6 ms·

is any of the dd tests actually valid? I don't see any of the options used that would bypass the cache.

• mitchty 9y ago
  dd, no, they're also setting bs=N which means they're testing the speed of /dev/zero copying to that block size as well. They also don't know if either hfs/hfs+/apfs have anything like zfs' "oh you wrote an entire block of zeros, yeah I'm not doing that, I'll just mark the block as all zeros" optimization. Never use dd to benchmark file i/o! At least use something like ioperf which has the ability to tell you more about what you're benchmarking. Using dd without bypassing any vm caches is... misguided at best.
• jedisct1 9y ago
  No. Wish they ran a real I/O benchmark program such as blogbench.