Raid or Mirroring 3 drives

Itsmittyhere

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Dec 30, 2018
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I am new to Freenas and I temporarily setup a server from an old Dell T5400, 1 quad core Xeon 2.66 GHz with 16GB memory. I successfully installed Freenas 11.2 with Plex server working, so I ordered 3 - 4TB HGST Ultrastar hard drives because a friend recommended running Raidz1. After a lot of reading I am thinking about 3 way mirror. I want to use it for photo's, home vid's, music and movies. I am new to using raid and I'm not sure the best option for my storage. Any suggestions would greatly be appreciated. Thanks in advance.
 
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garm

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Risk assessment is all up to you, but I wouldn’t run a 3-way mirror in a home server. Get yourself another drive and do two 2-way mirrors or RAIDz2
 

Itsmittyhere

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Risk assessment is all up to you, but I wouldn’t run a 3-way mirror in a home server. Get yourself another drive and do two 2-way mirrors or RAIDz2
Thanks for your reply.. I've read that Raidz1 has a good possibility of failing... if and when I need to replace a drive. This was the only reason I considered a 3 way mirror. My biggest concern is the photo's and home vid's , the other media is replaceable.
 

danb35

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I think the danger of RAIDZ1 is overstated, but nonetheless if you have data that's important I'd suggest something with more redundancy (keeping in mind that RAID is not a backup in any event). A three-way mirror would be safer than three disks in RAIDZ1, but would have half the capacity. I'd agree with @garm and recommend getting a fourth disk, and probably favor RAIDZ2 over striped mirrors.
 

Convict

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Risk assessment is all up to you, but I wouldn’t run a 3-way mirror in a home server. Get yourself another drive and do two 2-way mirrors or RAIDz2

Can you be more specific why you are not recommend 3-way mirror for home use ? Im asking because i was thinking more or less the same scenario for my data , Family Photos and Videos .

Thank you.
 

sretalla

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It is the only way to have dual-disk fault tolerance with 3 disks and it will perform well in comparison to RAIDZ1 on reads, but may prove disappointing on writes in comparison.

You'd probably be just as safe with a mirror and a single drive in another system with some kind of replication (replication task or rsync), which would then get you to a backup in addition to your fault-tolerant primary copy.

If you're really serious about not losing your data, you need a backup (either on a separate system at home, a family member or friend's house or in the cloud).
 

Itsmittyhere

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So I finally bought a 4th hdd, I currently have a triple mirror on 3 hdd's. When I add the 4th drive I want to change the raid array to RAIDz2. To my understanding you have to destroy the current raid array to change it. How do I do this? Storage>Pool>Add? I have backed up everything on 2 seperate hdd's in different pc.
 

IQless

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Feb 13, 2017
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So I finally bought a 4th hdd, I currently have a triple mirror on 3 hdd's. When I add the 4th drive I want to change the raid array to RAIDz2. To my understanding you have to destroy the current raid array to change it. How do I do this? Storage>Pool>Add? I have backed up everything on 2 separate hdd's in different pc.
Yes, if you want to switch from a mirror to RaidZ you would need to destroy the pool and recreate it as RaidZ2.
 
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