NAS at home, but which RAID setup?

Discussion in 'Off-Topic' started by Andrew21, Nov 13, 2017.

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  1. Andrew21

    Andrew21 "All Blade, All The Time" Administrator Advanced User Premium Member

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    Hey all,

    I just purchased a QNAP home raid system that can hold 4 drives. I've been out of the game for so long doing server stuff that I'm not sure which RAID setup I should use. I have 4-8TB drives for my home NAS. Reading up on it and people are saying use RAID 10. My friend who does server stuff was telling me to use RAID 5 because you don't have to lose a drive when you set it up. Been reading up on this but not so sure. What do you guys suggest?
     
  2. PY004

    PY004 Premium Member Beginner User Premium Member

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    RAID 5 should be fine for you and provide protection against single disk loss. Get that disk replaced in time and it should recover without issues.

    RAID 10 (in your case of 4 drives) will provide at least single disk redundancy, and someone's up to two disks depending on which drive fails. It's usually used for performance applications and as such ain't benefit you much since your already bottlenecked by your network.

    Use RAID5. you'll have more space to store things.
     
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  3. jon5

    jon5 PSL + (O / U) Intermediate User

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    RAID10. Because stressing over that RAID5 rebuild after a failure just isn't worth it.

    I've run both for systems exceeding 100tb. Do not play with RAID5 if your data is highly important. Especially if you use cheaper discs.
     
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  4. Andrew21

    Andrew21 "All Blade, All The Time" Administrator Advanced User Premium Member

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    Thanks Guys. I'm using the Western Digital 8TB red drives in my NAS
     
  5. PY004

    PY004 Premium Member Beginner User Premium Member

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    Andrew, what are you trying to do with this NAS? Based on what I think you will use for your NAS, my recommendation on RAID 5 still stands.

    In terms of data redundancy,
    RAID 6 > RAID 10 > RAID 5

    Time to rebuild (listed from shortest time to longest time)
    RAID 10 (least amount of time) > RAID 5 > RAID 6

    Performance impact during rebuild
    RAID 10 (least impact) > RAID 5 > RAID 6

    Read Performance
    RAID 5 > RAID 10 = RAID 6

    Write Performance
    RAID 10 > RAID 5 > RAID 6
     
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  6. Andrew21

    Andrew21 "All Blade, All The Time" Administrator Advanced User Premium Member

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    Thanks PY004. I'm not looking for speed right now but it looks like the Raid10 out performs Raid 5 in everything except Reading. Is there such a difference in read between the Raid5 and 10?
     
  7. PY004

    PY004 Premium Member Beginner User Premium Member

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    The performance aspect is not going to matter since you're still bottlenecked by the latency and bandwidth of your network.

    RAID 5 and 6's performance impact comes from writing where the NAS has to calculate parity for everything it writes. When reading, it just behaves as a stripe and RAID 5 has an advantage since it can read from 3 disks simultaneously vs 2 with the other two.

    Your main concern really comes down to how much capacity you need. RAID 10 will give you 16TB. RAID 5 will give you 24TB.
     
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  8. jon5

    jon5 PSL + (O / U) Intermediate User

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    Raid 5 read speed = s * (n-1)
    Raid 10 read speed = s * n

    Raid 5 write speed = s
    Raid 10 write speed = (s * n) / 2

    You're running WD-red, and a small raid, and you're not worried about speed, so RAID5 should work fine.
    We're you running lower quality discs, I'd still be saying 10. But your risk of getting a faulty cold disk is low.
     
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  9. Andrew21

    Andrew21 "All Blade, All The Time" Administrator Advanced User Premium Member

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    Thansk Guys..Raid 5 looks like the winner here
     
  10. jon5

    jon5 PSL + (O / U) Intermediate User

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    I do want to note that raid 10s read performance will always be 1 disk worth of speed better than raid 5. You can read a single strip (not stripe) from either of 2 mirrors, therefore a stripe can be read from all n discs simultaneously.

    This is contrary to what PY004 was saying.
     
  11. PY004

    PY004 Premium Member Beginner User Premium Member

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    RAID 10 offers read speeds up to nx in theory. In practice, it's more of (n/2)x. Very rare for a situation to rise in a home environment that can leverage nx with RAID 10.

    RAID 5 will give (n-1)x unless the host processor is fast enough to do the parity calculations real time (and the controller has the logic implemented to do this) in which case it can offer nx. The QNAP Andrew got I believe has this implemented. In any case though, a single WD Red 8TB tends to give more throughput than what his network can provide so it shouldn't be an issue. RAID 10 will also have better latency because of the dual spans. But again, this is negated by the latency of ethernet and the fact that in a home environment, he is unlikely to have multiple simultaneous latency critical uses makes the whole point moot.
     
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  12. tempnexus

    tempnexus The Glorious Leader Beginner User Premium Member

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    Are you using it for active backup? If so how many systems? What is the connection to the array? (Gigabit lan? Fibre? USB 3 etc)

    Also consider placing the box behind a home level UTM like SOPHOS SG 9.5 or XG 17, it's a free UTM and it allows you to VPN into your network from the outside whilst protecting your data from exfiltration. 24TB of data is a lot to loose.
     
  13. lamazing

    lamazing Learning to Drive General User

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    For home use and depending on your priorities, I'd go RAID 1, 5, or 6. If you have the option to do RAID 6, I'd do that. IMHO, RAID 10 is overkill for home. When someone requests for RAID 10 for one of our servers at work, I tend to ask them "why" and they usually have trouble explaining the need.

    (I'm a infrastructure SRE for large tech company and I'm frequently yelling at other coworkers to pick better RAID configs.)
     
  14. johnboy00

    johnboy00 Geaux Tigers! Beginner User Premium Member

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    I would never use RAID 5 personally. It was designed to maximize space when storage was expensive. Performance, especially on writes, is pretty poor. Use RAID 1 or 10 if you can afford it.
     
    Last edited: Nov 20, 2017 at 7:50 AM
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