Posted this thread in the beginners section, but didn't seem to get much of a response. Upon searching the forums it appears most ZFS issues have been posted in this Server section, so thought it was worth a shot.
Until recently I had been using mdadm with four drives, with each pair in a RAID1 configuration. These drives were 2x2TB, and 2x3TB, however as free space was very short, I purchased another 2x3TB drives with the intention of using mdadm and RAID5.
Upon building the RAID5 array, the initial sync was apparently going to take 11000 minutes to complete at a very slow 4500KB/s speed. I was advised that perhaps ZFS was the best way to go.
So, I installed a minimal version of ubuntu 13.04 and created my ZFS RAIDZ pool using all four 3TB drives (they are all Seagate ST3000DM001 drives), then created a dataset and attempted to copy a file to it... At a whopping 350KB/s!
The machine is a HP Microserver N40L with 8GB of RAM.
I have tested the drives with Windows installed on the same machine and get speeds of ~160MB/s per individual drive (same results in ubuntu using hdparm). I then tried FreeNAS on the machine and set up a ZFS RAIDZ pool using the web interface. I was only connected to a 100mb LAN connection at the time, but the file transfer saturated this connection as expected.
ubuntu-zfs was installed from the ppa:zfs-native/stable repository.
I used the following command to create the pool (serials omitted)
I really hope someone can help me out here, as I don't know why performance is so poor. I have seen online other people that have used the same hardware as me without this sort of issue.
sudo zpool create -o ashift=12 datapool raidz scsi-SATA_ST3000DM001 scsi-SATA_ST3000DM001 scsi-SATA_ST3000DM001 scsi-SATA_ST3000DM001
According to the ubuntu wiki page ubuntu-zfs is a "native kernel module".
Drives are updated to the latest firmware. I know they are cheap, but they are just being used for a simple home setup, nothing critical, and given their individual performance I cannot see why using them in this configuration would be an issue - they worked perfectly in the RAID1 array, and a software RAID5 array in Windows Server. Speed is not my top priority, if I only get 20MB/s, it's not ideal, but I can live with it.
I'm positive the CPU is up to the task as many people use this exact machine in this way, again, if I'm not seeing 200MB/s transfer speeds, I'm really not fussed. Likewise with the RAM, if 8GB isn't enough for maximum performance, I'm not fussed as long as it works without issues.
I do not mind which version of ubuntu I use, if 12.04 is recommended, I am happy to use that.
Given that FreeNAS ran so smoothly, and with decent transfer speeds (I may reinstall it to run a test over the gigabit network as this will be the main type of transfers I will be doing), surely the issue I am experiencing can only be down to software-based configurations rather than hardware limitations.