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Post by pbusardo on Nov 25, 2009 1:57:46 GMT 7
Ok, so I'm new to NAS RAID boxes and I'm very interested in the 4100Pro.
Here are my requirements.
1) I want to be able to start with 2 1 or 2 TB drives. 2) I want to have the maximum usabale drive space, but also want to be able to maintain my data in the event I lose a drive. 3) I want to be able to easily add additional drives later and make that space available for my data.
Can someone please guide me as to how I would have to set things up in order to achieve what I'm looking for?
I'm sure I'll have some followup questions as well.
Thanks so much for the support and information.
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Post by edgar on Nov 25, 2009 23:23:28 GMT 7
Hi,
As N4100Pro can handle 4 drives, that means your solution must : A - use less than 4 drives : you then have space for expansion B - use 4 drives of a given size (say 1 TB) : you will have to replace the drives with 1,5TB or 2TB later C - a mix of A & B.
As you want to maintain data in the event of drive failure, you need to use a RAID 1 or RAID 5 system. RAID 5 requires 3 drives. RAID 1 requires 2 drives.
Maximum average space using RAID 5 : (number_of_drives - 1) * size_of_drive. In other words, if you are using 3 drives you will have an average of 2 * the_smallest_drive_size available. Maximum average available = 2/3 = 66% of the_smallest_drive_size. If you are using 4 drives, maximum average available = 3/4 = 75% of the smallest_drive_size. I mention the_smallest_drive_size because you can mixe drives of different sizes (not recommended).
Maximum average space using RAID 1 : 1 * the_smallest_drive_size ! Event if you have 4 * 1TB drive as RAID 1 you will only have 1TB available !
So you should then go for RAID 5 with 4 drives (say 1TB). You could expect, an average available of 3 TB (2.8 TB in fact).
When you will need more space, use scenario B.
Il depends on your budget.
Regards Ed
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