Project: Building a cheap NAS, part 3

Filed Under (Storage, Windows Networking) by Just An Admin on 23-04-2011

Part 3: The controller and disks

Our server parts are coming together nicely. The chassis, motherboard, memory and processor have been added to our wish list. Now it is time to look at the expansion SATA controller and the disk we would like to use.

The controller

Again the choice of brand is forced by several ‘demands’ we have.



The controller must:

  • support 8 SATA disks
  • be supported by FreeBSD/FreeNAS
  • have a decent throughput / IO’s per second
  • have PCI-E 8x support, but most controllers are
  • be affordable

Looking around different forums, the choice of controller was easy. Most controllers that are offered are geared towards RAID setups. The general opinion is: don’t make it to complex and go for an Intel SASUC8I with a LSI 1068e as base. And as the costs for this card was very attractive, this was no hard decision to make.With 140,000 I/Os per second and great compatibility, we don’t think this controller will become a problem.

As we are going to experiment with the ZFS file system, we don’t need controllers that offer RAID support. This little controller can be altered with another firmware to act as a simple JBOD controller, also called ‘IT-mode’, which does wonders for our planned ZFS setup as it offers the attached disk as separate disk to the OS without interference of any RAID. We still have this option under review and will address this again once we move to the installation part of our project.

Review of the Intel SASUC8I controller.

The disks

Now about the disks…. There are a lot of good brands out there and most offer very good products. So looking for 2TB disks we had several options. Again we had to find a reasonable priced disk that offers great performance and is reliable.

Western Digital has a 2TB Green disk (WD20EARS) for a good price. They are silent, energy efficient (read: not to hot) and have 64MB cache. Normally, big on-disk cache is only advised in RAID setups if you have your server running on a back-up power source (UPS).  The disk uses 4K sectors that has a lot of discussion going on the forums. Read them before you decide to use this type of disk so you know what you are getting in to. One and a half years after they first appeared on the market, support for these disks has been integrated in most software solutions, like FreeNAS or have solutions or workarounds to prevent slowdowns due to misalignment of the disk partition due to the 4K sector size.

Performance wise these disk compare good to other brands like Seagate Barracuda and Samsung SpinPoint. I know there are a lot of NAS owners here that would favor one of the other brands, but reading a review on the Western Digital 2TB Green Disk at StorageReview.com has confirmed my choice.

Review of the Western Digital WD20EARS Green Disk.

We are more than comfortable using these disk in our setup and put 10 of them on our wish list.

Reading more about this disk learned thatwe need to be looking for 3-platter ones (WD20EARS-00MVWB0), because the 4-platter version (WD20EARS-00S8B1) is a slower and consumes more power (=heat).

The disks cost us 72 euro’s each and the controller set us back 119 euro. That is a grand total of 839 euro on the storage department.

But we are not finished.

Booting the FreeNAS OS from one of the 2TB disks would be a waste of good storage space. Since FreeNAS is able to boot from USB and we selected a motherboard that has an onboard USB connector (what a coincidence), we need a good USB memory stick. As we are nitpicking specs on every product we need, we would not pass on doing the same for our USB memory stick.

Again performance and price determine the choice of product. Looking through many, many kinds and brands and types of memory sticks, one caught our attention. The Kingston DataTraveler R500 16GB. This memory stick offer enough storage to hold several FreeNAS installs or back-ups. But the reason we like this memory stick is for three reasons:

  1. The sticks has a read/write speed of 30MegaByte read and 20MegaByte write. These are great speeds when compared to the standard USB memory sticks that generally offer 10MegaByte read and 5MegaByte write.
  2. Its casing is rubber-foam coated, protecting the memory stick itself and as it sticking out our motherboard, i would like to stay away from anything metal.
  3. It isn’t that expensive. It will cost us 28 Euro. I’ve seen regular memory sticks of 16GB for more.

To be continued!

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