Read speeds are half of write speed

[techweenie]

This is my first time using nas4free, so bear with me. I have an old Intel socket M mini-itx motherboard with a Core 2 Duo T7200 and 3GB DDR2 RAM. It has two 4TB Toshiba hard drives connected to the onboard ICH7 interface. It also has dual on-board Intel Pro/1000 NICs. I configured the drives in software RAID 0 and formatted it UFS to use for storing backups. I don't need any of the ZFS features for that.

I setup a SMB3 share and tested performance by copying a 3GB Windows 7 ISO file to and from it. Write speeds consistently peg the gigabit eithernet, but reading the file back will never go faster than about 70MB/sec, and typically settles around 60MB/sec. I've tried setting the send/receive buffers to 0 as suggested in some other threads but that didn't seem to change anything. How can I get better read speeds? This is important because I have over 3TB worth of data that must be backed up and later restored to a new server. Once the new server is operational the nas4free box will only be used for storing backups and later on replication offsite.

[Snapshot]

I have the same problem and also haven't had it answered. I thought it might be a nasty NIC on the ASRock AMD mobo but it's not that if you're getting it with Intel NICs. My system has a AMD 2.0GHz quad-core CPU & 8GB of RAM so it's not short of grunt. There are four WD Red 2TB HDDs in ZFS raidz1. I've enabled Jumbo Frames on the NICs in all PCs and servers and set the MTU to 9000.