Project: Building a cheap NAS, part 1

Filed Under (Storage, VMWare ESXi 4, Windows Networking) by Just An Admin on 14-04-2011

A NAS storage is no longer a luxury for the big companies that are able to spend 5-6 figures. For the last few years NAS storage has become a common product even to be found in small offices and home environments. Most of these products perform pretty good out-of-the-box and do exactly what they where designed to do; Store data and make it accessible through different protocols.

But….. i am looking for more. Most 4 to 6 drive solutions do not offer me the Terra-bytes needed to store my data. I need more and I’m not willing to pay an arm and a leg to get it. So I decided to build my own hardware setup and use FreeNAS to build our own NAS storage.

I’m going to build this unit on borrowed knowledge and good common sense.  There are some pretty decent sources of information on the web, like the FreeNAS community or different public community forums. And a lot of DiY NAS builders that have paved the way.

Our goal

Create a NAS Storage that meets the following requirement:

– must be able to hold 16-20 disks, SATA2 and/or SAS and 2TB per disk. Initial requirement is 10 disks of 2TB.
– must be hot-swappable hardware and redundant disk setup/file system
– must be able to perform in a business environment (multiple servers, users) using iSCSI, AFP and SMB/SAMBA/CIFS
– must be supported in a VMware ESXi or Microsoft Hyper-V Server environment
– must be a 19 inch chassis
– must be under 2000 euro (not including taxes and shipment). We need to watch the cash….
– must be hardware compatible with FreeNAS 7.3/8.0 (RC4 at time of writing)
– at least two PCI-E 8x or PCI-E 16x slots to support future expansions (controller or LAN)

And we have a wish list too:

– support for webdav or a means to publish user home folders to outdoor and home workplaces or mobile devices
– support for redundant power supply
– if possible, three PCI-E 8x or PCI-E 16x slots to support future expansions (controller or LAN)
– Two or more NIC’s that support Teaming or Link aggregation
– Onboard USB connector to hold the USB memory stick with the FreeNAS Operating System

As we do not know what to expect performance wise, we did not set a goal regarding speed. But it is clear we are aiming for the best possible. A little study into the experience of other FreeNAS users learns that 40-50MByte per second is a good first aim.

Part 1: The casing

There are several vendors that offer casings or chassis to support 16 to 20 drives in a 19 inch, like Norco, SuperMicro or Chenbro.

We would like to limit the size to a 4U chassis. We decided to go for the Norco RPC-4220 with 20 separate hot-swap 3.5Inch SAS/SATA drive bays. This chassis has 5 internal SFF-8087 Mini SAS backplane connectors, each supporting 4 drives. The backplanes are horizontally mounted for better ventilation. Besides the 20 hot-swap bays there is also room to house 1x slim CD-ROM player (hot-swappable) and two 2.5″ drive brackets. This chassis also supports redundant power supply.
Besides a 20 disk model, there is a little brother that can hold 16 hot-swappable drives and a bigger model that can house 24 hot-swappable drives. This last chassis would require the support of 16 port SATA/SAS controllers making our project very expensive, as three 8-ports controllers would fill up all the slots on many motherboard, leaving no room for future expansions.

There is also room for an optional 120mm Fan Wall Bracket. This allows for better air flow through our case. Since we are not using any ‘ High Temperature’ parts and as this unit will be placed in a conditioned server room, we did not purchase this upgrade.

The 20-bay chassis will cost us 345 euro, but still requires a power supply and the necessary cabling to connect the disk backplanes to a motherboard or controller. We bought this unit directly from the European Distributor of Norco (

To be continued!

Note: While browsing for experiences from other users using this chassis, i came across this useful post: It explains the use of the air vents in the disk trays to direct air through used bays and stop airflow through unused trays; a feature that may be easily overlooked as the unit comes without manual.

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