Husein Rajgara :
I agree with what you guys say, however i have already placed order for the Fractal Design cabinet node 804, and since this isint available in my country it would take about a week to arrive. I am actually selling my buffalo linkstation to a mate and i shall be just backing up on the new NAS i build.
I have zero'ed in on these items:
gigabyte-ga-h97m-d3h
2 x 4GB corsair DDR3 1333
Intel dual core G3240 CPU
Corsair CS550 SMPS 80+gold certified
Regarding HDD since anything over 4TB isint easily available where i live i plan on getting 3 of these to start with.
Upon reading a bit about the OS to setup i am confused between FreeNAS & unRAID both have its advantages and disadvantes offcoure however i want to loose the least amount of HDD's while being about to have data backups aswell and i read FreeNAS with ZFS works kinda well for this? As it needs only 1 HDD for backup?
The number of drives for similar storage space is the same for FreeNas (ZFS) and unRAID. They both use a form of RAID 5 but implement it in different ways. RAID 5 means that your storage space is equal to the the number of drives - 1. If you have 4 x 3TB HDDs then your array is 9TB. The remaining 3TB of space contains parity information so that if a drive fails, you swap it out, run a rebuild and your data is restored. That is where the similarity ends.
FreeNAS uses the ZFS file system and its version of RAID 5 is called RAID Z1. Unlike unRAID, ZFS stripes the data across all of the drives. A large file would, quite literally, be spread across all of the drives in the array. It makes accessing the data much faster than storing the data on just one drive since the server can read data from several disks at once. The ZFS file system is very robust with built in features that detect data rot and error correction. FreeNAS (ZFS) is usually better off with higher end hardware and ECC memory (RAM), and a lot of it, is strongly recommended. In fact it is recommended to have at least 1GB of memory for every TB of storage space for ZFS to run smoothly. Also, all of the HDDs in the array need to be the same size or you simply lose any storage space on any disks that are larger than the smallest in the array (if you have a 2TB and 2 x 1TB drives then then FreeNAS will treat all drives like they are 1TB and you lose the 2nd TB on the bigger drive). Because the data is striped, you cannot add more drives to the array once it has been built with out wiping the array (which deletes any data stored on it) and then completely rebuilding it. You can always pool multiple arrays together. FreeNAS uses a little more energy since all the drives in the array must be spun up to access data.
unRAID was actually designed to be built from spare parts you have lying around that you can repurpose into a media server for storing music, movies, etc. Because of this, the hardware requirements are bare minimum. People are regularly using old single core Semprons and 1GB of memory tossed into an old computer case. It runs its own version of RAID 5, but unlike ZFS, it doesn't stripe the data across all of the HDDs. All parity for the array is stored on 1 HDD that is designated as the parity drive. Then the actual files are stored on one of the data drives in the array. If you have 4 x 3TB HDDs then 1 will be the parity drive and the other 3 will store the array's data. Also, you can use any size HDD and be able to use all of the space on the HDDs with the rule that the parity drive has to be at least as big as the largest data drive in the array. You can mix 2 x 2TB drives with 3 x 1TB drives and have 5TB of storage (2TB parity, 2TB Data, 3 x 1TB Data). It works on the same idea as the rest of the hardware in that you can just throw some old drive in the array and the array is expanded by the size of the new HDD. unRAID is slower than FreeNAS because the data is read off of just one drive at a time. However, there's also the advantage that if your array completely crashes and you lose 2 HDDs at the same time, making it impossible to recover the array, you only lose the data on the drives that crashed. Because the files are stored completely on 1 disk you can just plug each drive into a Linux machine and read the data off of them outside of unRAID.
unRAID is cheaper to implement, lighter on resources and power consumption, is easily expanded in the future and is very much intended to be used as a home server. FreeNAS is faster, has a more robust file system and is more of an enterprise class of system. The CPU you have chosen is fine for either system, but if you are thinking using FreeNAS you should consider more memory and make it ECC if at all possible.
And, to throw in the expected disclaimer, especially because you stated it this way.......
RAID is NOT backup. RAID systems like unRAID and FreeNAS are implemented with the idea of keeping the array online and running (in a degraded state) in the event that a HDD fails so that data can continue to be accessed until the time is right to repair and rebuild. RAID will not protect you from accidental deletions, viruses, fire, flood, electrical surges, a bad motherboard, untimely formats, etc. Have a backup plan in place for any data that is critical.