From what I got from ZFS it will use the block size reported by the device and at least for the WD EARS hdds this is 512 byte. So even if you align your partitions perfectly to the 4k boundaries (or use the full hdd), you'll get <4k writes. In those cases the drive has to read the 4k block first before writing the changed part.
Originally Posted by baryluk
Easy question about the Fuse ZFS:
Is it good enough for a NAS? I care about data integrity, and could live with speeds of 50 MB/s in RaidZ modes.
In my testing, sequential read speeds are almost platter. Sequential write speeds are substantially lower (like half of platter). But with a RAIDZ of 3 drives, you will be able to beat 50MB/s sequential write speed even with low end 7200rpm drives.
Originally Posted by marakaid
So, yeah. zfs-fuse is ideal for your requirement. You have to throw enough RAM at it(512MB is not enough, I have mine at 1.5GB).
Data integrity is super awesome! I have already seen a sample of it when I one of my older files developed a bad block (no idea if the drive introduced the error or what the cause was).
I'd like to see a benchmark that times how long it takes to remove a disk from a ZFS mirror.