“The art of a warrior is to balance the terror of being a man with the wonder of being a man.”
Carlos Castaneda

Journey to Ixtlan

Homemade RAID (Part2) – Hardware

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My hardware configuration requirements were largely decided by the core of the system – the hard drives. I had hoped to utilize a decommissioned computer (or parts of it) – but that didn’t really work out. Read on to find out what decision shaped the hardware configurations and choices.

Hard Drives

At any given time there are cost effective hard drives on the market (the lowest price per gigabyte). At the time that I constructed my system these were 500GB drives, but I opted for larger 750GB drives. The reason was that I could use fewer hard drives to achieve a larger overall capacity (If you recall one hard drive in a RAID5 array is a parity drive so: 4x750GB drives = 3×750~2.25 Terabytes, 5x500GB drives = 4×500~2 Terabytes). Why would I want to use fewer hard drives? Two reasons (1) SATA ports and (2) chassis.

SATA Ports

Though I am building a software RAID – I still needed to get the all the hard drives connected to SATA ports. There are two sources of SATA ports on a computer: (1) native ports installed on the motherboard and (2) extension ports supplied through extension cards.

I did some research on SATA extension cards and came up with unfavorable results. One key difference between Linux and Windows is driver compatibility. Windows is well known for it’s infinite repository of compatible drivers. Linux is much more limited. Though there are SATA extension cards on the martket – it is unclear if they are compatible with Linux. Most of the companies that I found do not have Linux on their OS compatibility list. I did find two manufacturers Adaptec & 3Ware both of whose devices are Linux compatible (at least by declaration) – but they are not just extended SATA ports – they include a complete hardware RAID solution. They are relatively expensive and out of range for my low-cost solution.

Motherboard

I therefore opted to go for a solution where all SATA ports are provided by the motherboard. This immediately narrowed the search down to motherboards with 6 or more SATA ports. Why 6? Remember I am trying to build two RAID arrays. One RAID0 (mirroring) array – 2 drives for the operating system and the other RAID5 (striping with parity) array – 4 drives for the sctual storage space = total 6 drives.

In the end the search was narrowed down to two candidates: an Intel motherboard with 6 SATA ports and a Gigabyte motherboard with 8 SATA ports. I went with the Intel motherboard (though I preferred the Gigabyte) because of warranty and service in Israel. Intel has great service, Gigabyte less so. Great service means quick replacement – so my system can be back online in no time if something does go wrong.

There is one feature on the Gigabyte motherboard that is not available on the Intel motherboard. I had planned to use the motherboard’s hardware RAID capabilities (both have it) to create the RAID0 mirroring for the operating system drives. I cannot do this on the Intel since the RAID setting applied to all the hard drives – so I cannot single out two drives. On the Gigabyte motherboard the 8 SATA ports are divided into two groups: 2 ports & 6 ports. Each can be configured as a RAID device using the motherboard’s hardware controller. This would have enabled me to attach the operating system drives to the 2 port group and have the mirrored using the motherboard capabilities.

Chassis (Computer Case)

The key requirements for the chassis were as many (internal 3.5″) drive bays as possible and a good cooling infrastructure. There are many chassis makers and and models – as always it is a balance of price per value. I found a great chassis by Chieftec – mid priced with excellent features. It has a dedicated storage for 6 3.5″ had drives that faces outward and provides tool-free drive installation (very convnienent no more screws). When you purchase your hard drives try to get your hands on SATA cables that have a 90 degree bend – they compliment the case well. I furnished it with all the possible fans.

Additional Computer Parts

  • I added a 550W quality (mid priced) power supply.
  • I installed a 7200 series Intel processor (this computer does not require a powerful processor)
  • I installed 2GB of RAM (2x1GB)
  • I was able to utilize a combo DVD burner and a floppy from the decommissioned computer.

Additional Accessories:

  • A network cable.
  • A 1000Gb ethernet switch (to enjoy a fast connection between the server and other computers on the network that have 1000Gb ethernet devices).
  • A cross-cable to connect my router to the switch.
  • A power cable or adapter to hook up the server to the UPS.
  • A keyboard and mouse (had a spare set)

Thoughts on KVM

I intended to get a USB KVM switch – but couldn’t seem to find one that is affordable and reliable (there are some cheap ones – bu user experience and reviews are not good and the more reliable ones are too expensive for my budget and needs). So for now I need to reconnect the screen cable from one machine to another to work on the server. But eventually there is little need to access the server so this is not a real issue.

I have also come to learn about VNC – a software application (actually it is a communication protocol – so there are numerous VNC software packages) that provides remote desktop control over the network (so I can control my server from any other desktop computer). I haven’t been able to get this to work yet.

Coming next – Server Installation

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