Having gradually built up my media collection to near the capacity of my 16TB external HDD, I’ve reached the point where I’ll probably need to build a RAID array to keep the collection in one place. Assuming the RAID array will be at least 32TB, I have a few questions:
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From what I’ve read RAID arrays can help mitigate the risk of individual drives failing if extra space is allotted on the hard drives. Assuming a total capacity of 32TB, how much of that space would be reserved by the RAID array for data loss prevention?
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Is there a certain type of hard drive I would have to use? Aside from my 16TB drive, I also have two 2 8TB drives that I’d ideally like to be able to re-use in the RAID array, but have left them in their enclosures for the time being.
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If the hard drives in the array have different transfer speeds, does the array as a whole default to the slowest one?
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Whether the hard drives I already have are compatible or not, what RAID enclosure and hard drives would you recommend?
RAID for uptime, backups for data you care about. RAID(1+) will keep your data online when a disk fails, but backups are the real way to keep data around if shit hits the fan. For a personal media collection, you might be better served with a non resilient RAID0 (total failure if one drive fails) with a backup around to recover from when that happens. If you do e.g. a raid5 you lose 1 disk of capacity in exchange for 1 disk of resiliency, raid6 same but 2 disks. That gives you some safety but there are a lot of instances where those raids don’t save you from losing all your data. If you buy 4x 18TB drives, you could have 36TB from the 1st two drives and then backup to the other two drives.
There’s no specific type of drive to worry about unless you’re doing RAIDs especially with ZFS. Search shingle RAID rebuild for the biggest thing to worry about there.
Almost always, yes. Slow drives throttle the rest.
I’ve never used them but people say good things about synology most of the time. Everything comes with a cost and it’s hard to make any sensible recommendations without knowing your constraints; primarily your budget.
Want to echo what was said here. RAID is not a backup solution. RAID is for always on capability. Do not use RAID as a way to keep valuable data safe. Just have double the drive space and keep a backup of the data on the second drive.