RAID 5: 6x 2TB drives or 4x 4TB drives?

Discussion in 'Buying Tips and Advice' started by alphaod, Dec 13, 2012.

  1. alphaod, Dec 13, 2012
    Last edited: Dec 13, 2012

    macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    上海 (Shanghai)
    #1
    I'm adding a new karaoke system at home and I'm planning to use a RAID 5 to store the music videos required for the system. I have almost 10TB worth of videos.

    There are two configurations I am considering:
    1) 6x 2TB drives for 10TB total.
    2) 4x 4TB drives for 12TB total.

    With (1) I have higher throughput from the increase number of drives, the drives themselves are cheaper, but if I need to add more music, I need to add another drive to the RAID which I would want to avoid. I also need a chassis to support 6 drives and in the future 7 or 8 drives; I also would need a RAID controller with more ports for this. Price of this would be $1440.

    With (2) I would have 2TB of free space to start which should be useful for expansion. I can get a slight cheaper RAID controller since I only need 4 ports right now. There is less drives so I don't need an enormous computer chassis for the build. The drawbacks I see is mainly the 4TB drive has crazy density which I find could be a problem. These disks are also very expensive right now, and a failure I imagine would take a very long time to rebuild. Performance will probably be lower due to few disks. Price of this system would be $1900 which is about $450 more than the former which I think would be the cost of two additional drives.

    Being all videos, I don't think I need random performance which is why I don't think I should use SSDs (not to mention I would need some 22 of them which is very expensive, some $8800).

    I guess I could use 5x 3TB disks, for $1700 which isn't much cheaper using a 4TB disk system which would use a cheaper RAID adapter.

    Any thoughts on this?
     
  2. macrumors 68030

    andalusia

    Joined:
    Apr 10, 2009
    Location:
    Manchester, UK
    #2
    You're spending ~$1500 on a karaoke machine?! :eek: I wouldn't have thought a home karaoke set up would be worth that to anybody..
     
  3. macrumors regular

    Joined:
    Aug 31, 2010
    #3
    Raid 5? I would think twice. Google to find out.

    Raid 10.

    Depends how precious you are about your data.

    Additionally, RAID isn't a backup, just in case you had not realised.

    Depending on your expansion requirements and budget, if you have a lower budget I would go for the 2TB disks as they are much more economical, you will have larger IOPS and thus, better performance due to a larger number of disks, however, if you are going to need to expand extensively 4TB might be your better option.

    Good luck :)

    De
     
  4. macrumors 6502

    davegoody

    Joined:
    Apr 9, 2003
    Location:
    Reading, Berkshire, England
    #4
    RAID can be used as backup

    RAID CAN be a backup........

    No reason why not, and FAR faster than most other backup solutions. However so long as it IS set as a backup, i.e. not used for Storage too.

    So have all your main data somewhere else, and RAID 5 is great as the backup destination. As for RAID5 not being good...... I have been using RAID5 for years in serious Enterprise ready applications, and it is fine. Again, different levels of RAID exist at different price points so use what you need at the price you can afford.
     
  5. macrumors regular

    Joined:
    Aug 31, 2010
    #5
    I think you need to read what I wrote again :)

    If you are using RAID for your main data and not as a backup destination(as stated in the original post)then RAID is not a backup, it's a method of increasing your redundancy through some very smart methods(depending on what RAID you use)

    If you are using a backup target and it's on a RAID5 fine, up to you. Ideally your main data should be on a RAID10.

    Issues with RAID5 can be checked on Google, also have a look at the many posts on Spiceworks.

    Of course RAID5 is fine, until something goes wrong, then it isn't :)

    I use big toys too, it's fun.
     
  6. thread starter macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    上海 (Shanghai)
    #6
    I already have an existing system; with TV speakers, mixers, wireless mics, my existing system. I take my karaoke very seriously, and being Asian it's a family pastime. ;)

    I'm simply updating to a new one with more music. I have moving a lot of the parts over, but my existing system doesn't have enough storage, so I'm putting a RAID 5 together for the music required for the system.

    The RAID isn't for backup. I have a backup. The RAID is so I don't have to spend time rebuilding the system should a drive die.

    I considered RAID 10. The issue is the fact that I would need twice as many member disks instead of X+1 for RAID 5.

    I know the drawbacks of RAID 5. I have been running one in my Mac Pro for over 3 years now. I will have a battery backup for the RAID host adapter, though there won't be many write ops if any at all.
     
  7. throAU, Dec 17, 2012
    Last edited: Dec 17, 2012

    macrumors 68030

    Joined:
    Feb 13, 2012
    Location:
    Perth, Western Australia
    #7
    Being mostly READ biased, i'd go for 5 drive RAID5 with a hot spare.

    You'll get good read performance, crappy re-write performance, but at least you'll have a hot spare for when one of the disks goes pear shaped.



    Standard RAID5 disclaimer applies: most array vendors are strongly suggesting NOT using RAID5 or RAID50 with SATA drives of >1tb, as they take too long to rebuild, and during a rebuild the non-failed drives will be under a lot more stress, meaning they're moer likely to fail.

    Obviously thats in an enterprise scenario, but there you go....


    edit:
    Have you consisdered running FreeNAS and ZFS as the storage back end? Rebuilds will be faster...


    Also, be aware: unless your drives have TLER support (WD naming other vendors call it something else - essentially RAID specific time out for error recovery) they may cause failures with a hardware RAID controller. Typically, cheap, large sata drives do not have this unless they are "Designed for RAID".
     
  8. macrumors 68030

    andalusia

    Joined:
    Apr 10, 2009
    Location:
    Manchester, UK
    #8
    I hadn't realised it was a common theme with the Asian community. Sounds competetive though....
     
  9. thread starter macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    上海 (Shanghai)
    #9
    I decided to go with the 2TB disks.

    I got my drives today and just finished building the system.

    Nah it's good fun. Especially after a lot of drinking.
     
  10. macrumors regular

    Joined:
    Aug 31, 2010
    #10
    Did you go for the 2TB due to price?

    Good system, irrespective of what size :)

    Thanks for the update
     
  11. thread starter macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    上海 (Shanghai)
    #11
    Yeah. 4TB are too expensive at this point. The difference was $500 between using 4x 4TB and 6x 2TB disks (and I bought 7x 2TB disks, so I have one for a hot spare).

    Also I found my old motherboard did not have enough PCI Express slots (I needed 3 of them), so I ended up getting a new motherboard and CPU as well. I think I went a bit overboard with the CPU; way more than I need.

    The whole system looks great, is almost silent, and weighs like a tank (housing 7 HDDs along with a water cooling radiator)
     

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