The eTeknix Guide To Building Your Own NAS

BIOS Tweaking, Performance and Power Consumption

BIOS Tweaking

One of the advantages of a purpose-built NAS is that it is built from the ground up in terms of software and hardware to be a NAS. Conversely that means one of the weaknesses of a DIY NAS like this is that it isn’t entirely designed to be a NAS, as a result you need to make smart hardware and software decisions to make it a better NAS. Some of those will need to be made in the BIOS to ensure more efficient operation as power consumption is a vital aspect of any NAS system as they will likely be on close to 24/7. Some of the tweaks I made and you might consider making are:

• Turning off Turbo Technology: turbo speeds are great for desktop PCs but in a NAS you will see little benefit from it other than higher power consumption and more heat. This is a setting to keep off unless you are really pushing your NAS with lots of disks and constant demanding use scenarios.
• Lowering the CPU multiplier: by default this APU runs at 3.2GHz across two cores which is total overkill. I have lowered this to the minimum 14X multiplier or 1.4GHz, this is still way more CPU power than is needed for 2 disk NAS. If you were adding more disks you should consider running a higher clock speed because more disks require more processing power when being accessed.
• Lowering the CPU voltage: even at stock speeds most CPUs have scope for reduced voltage, the A4-4000 has a 1.325-1.35 stock voltage, I lowered this to 1.1 volts and the system is still stable.
• Lowering the GPU Frequency: the use for the GPU is purely for display purposes when setting up, once you’re managing your NAS by the WebGUI the GPU is redundant so forcing the lowest clock will ensure the lowest power consumption.
• Setting silent fan profiles: Most NAS systems will produce minimal heat and require only minimal airflow to dissipate the heat from the hard drives. You also want it to be quiet so setting a silent fan profile is a great way to minimise noise and power consumption.
• Fixing integrated graphics memory: by default the APU will use 512MB or more video memory, as we’ve mentioned already the GPU is barely used so you can comfortably set this to a lower setting (64/128/256MB) in order to free up more system memory for hard disk management.
• Disabling unnecessary devices: the onboard audio, serial ports, TPM ports, parallel ports and front panel USB are all unnecessary so you can turn them off in the BIOS to save power.
• S.M.A.R.T: Self-Monitoring, Analysis and Reporting Technology allows hard drives to report system health to the operating system, turning this on is useful as it allows you to manage your disks better. Generally speaking hard disks aren’t “smart” enough to tell you when they will fail, but the SMART indicators can give some early warning signs of potential failures.

Performance

The performance of a NAS is going to be variable depending on a lot of things, these include: whether you’re accessing from a wired or wireless device, what standards of connectivity those wired and wireless devices use, what size files you’re moving, whether you’re reading or writing and so on. For our tests we’ve tried to simplify things a bit and show some realistic scenarios. Firstly, we tested LAN Speed Test Lite using a 1000MB file which is written to the NAS storage from an Intel-Gigabit enabled Windows 7 PC, then read back once the write is complete. On the upload the speed was very impressive and at 770 Mbps or 96.25 MB/s, this is able to take advantage of the Gigabit controller the NAS provides. In my honest opinion 96.25MB/s is probably a hard drive related bottleneck. On the download we achieved quite a lot more with 876 mbps which is 109.5 MB/s. This is more likely to be a network controller limitation as most hard drives will do 120-140MB/s on the reads and I know a lot of Gigabit NICs top out at 850-900 mbps on this test based on my experiences with a lot of motherboards I have reviewed.

Onto a more real world test and I tried moving a 2GB 1080p film from an Intel-Gigabit Windows 7 PC to the NAS, then read the same file back from the NAS to a different directory on the Windows 7 PC. This test gave similar results to the LAN Speed Test Lite benchmark revealing the read is a lot faster than the write at 111.1 MB/s (888.8 mbps) while the write sat at 89.6 MB/s (716.8 mbps). Again I believe the hard drive is the limiting factor on the write while the Gigabit ethernet limits the read. Either way though these are some seriously fast speeds but the obvious thing worth noting is to get these you’re going to need:

• Gigabit Network Interface Controllers (NICs) in all sending/receiving clients to the NAS server
• Cat 5e or Cat 6 Gigabit rated ethernet cables
• Gigabit rated switches or routers connecting the client to the NAS server

Remember any network file transfer is only as fast as the slowest link in the chain, the important thing is to consider the pathways taken between the server (the DIY NAS) and the client (the system sending or receiving files from the server). WiFi transfers (such as to phones, tablets, laptops and so on) will be limited by the speed of the wireless adapter on those client devices, typically these will be 802.11 N so will be much slower than wired transfers.

Power Consumption

Moving on to the power consumption and the results are fairly impressive, even when compared to dedicated NAS systems. Despite this being a fully fledged computer system we see just 39.5W with the NAS server in idle and always-on hard drives. You can set the hard drives to sleep on inactivity but this is known to reduce hard drive life-span so we’ve left them always on. Below you can see that the NAS box never really exceeded 50W under load which is fairly impressive. These tests were all performed from one client machine, if you added additional read and write tasks from additional clients you would probably be able to add more to the power consumption, but I think the take home message is that the system is incredibly power efficient. This is down to two main things:

1. The quality and efficiency of the SilverStone power supply.
2. The quality and efficiency of the Western Digital 2TB NAS drives which have specific power optimisations for NAS usage scenarios.