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Which raid is best suited for a multi media server which will be streaming content (movies/music/large data) to multiple clients simultaneously (10 or so for now, more in the future).

This server will also be used for development (scripting, and web development using nginx/php stack), virtual machines via QEMU and lan game servers.

The main feature I am looking for I assume is speed and data reliability in which if one drive fails the raid can still function. Along with this I am looking for a raid which allows future drives (2tb each drive) to be added easily without needing to reimage everything. I plan on starting with 2 drives and working my way up to 6 total adding 1-2 drives as space is needed.

My hardware raid controller is a ServeRAID-8k which supports raid 0, 1, 10, 1e, 5, 6 (and possibly others if I update my firmware).

If someone could explain why the specific raid they chose would benefit this setup as well I would appreciate it.

Thanks for any help.

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  • I highly recommend not using hardware raid, also. Commented May 3, 2017 at 21:29

1 Answer 1

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If you're starting with 2 drives your only two choices are RAID 1 and 0 as these modes only require a minimum of 2 drives, with RAID 10 requiring 4 and RAID 5/6 requiring 4 as well. However, if you were to go straight in with 6 drives, I would be putting in a RAID 6. If you have a hardware RAID controller, performance won't be affected much (assuming that the RAID controller is up to the task and how much throughput you're hitting the RAID config with) and with RAID 6 two drives can fail before your data becomes at risk. RAID 6's are fairly easy to expand into, but you'd already have 6 drives in there. Expandability really depends on what hardware/software you're using in most cases, and so you'll have to look up on your hardware's manual on how to expand the RAID volumes. If you were to start with 4 drives, I'd go with a RAID 10 (and even stay with RAID 10 when you get your 6 drives). RAID 10 combines RAID 1 and 0. That is, it combines the speed you get from RAID 0 by striping two HDDs, but then gives you the redundancy of RAID 1 by making a span of that RAID 0. Overall, RAID 10 gives you redundancy and extra speed, but only 1 drive can fail in RAID 10 before your data is at risk.

SO, an overview of your choices:

  • 2 Drives - your only options are really RAID 1 and 0. I'd be going with RAID 1 for redundancy here. RAID 0 if redundancy isn't important.
  • 4 Drives (and up to 6) - RAID 10 for redundancy and extra speed. Again, RAID 0 if redundancy isn't important.
  • 6 Drives - RAID 6 for 2 drive redundancy, if uptime is a huge issue for you, or just plain old RAID 10 if uptime doesn't matter a huge deal. Again, RAID 0 if redundancy isn't important.

UPDATE
An overview of RAID:

RAID 1: 1 Disk is used for storage, the other used for parity. Disks can only be added in 2s in RAID 1. If 2 2TB drives are in a RAID 1 array, only 2TB of hard drive space will be available

RAID 0: 2 Disks are striped, halving the data onto each disk. Disks can be added in 1s, although performance increase decrease the more disks that are added (diminishing returns). All data from hard drives is usable.

RAID 10: 4 Disks required, minimum. Creates a RAID 0 array from 2 disks, then creates parity for those 2 disks on another 2 disks. Drives must be added in pairs. Combines redundancy and speed, with half of the drive space usable - i.e. 4, 2TB drives results in 4TB of usable space

RAID 5: 4 Disks required, minimum. One disk becomes a parity disk for the other 3. Often no performance increase with this setup, however disks can be added in 1s with RAID 5. Drive usable space is 3/4 of total drive space, however only 1 disk stays as parity i.e. 4, 2TB drives results in 6TB usable space; 5, 2TB drives results in 8TB usable space. RAID 5 does have a drive limit, however it is not worth mentioning as your setup will not reach this limit.

RAID 6: 4 Disks required, minimum. Two disks become parity, with the other 2 used for volume space. Drives can be added in 1s. 2 Disks can fail in this setup before data corruption/loss starts to become an issue. With 4 drives, half of drive space is usable, however only two disks are parity regardless of total volume disks. i.e. 4, 2TB drives gives 4TB usable space; 5, 2TB drives gives 6TB usable space.

And a final note: RAID configurations are NOT a substitute for backups.

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  • How is the space affected between the raid configs? Will raid any of the raids reduce my total space available? If redundancy is taken out of the question (I keep backups to separate drives) should I just do a raid 0 array? Or is the other raid levels still better overall? Uptime isn't much of a factor since the server is for a home and will have frequent reboots for kernel rebuilds.
    – user419541
    Commented Nov 21, 2015 at 3:42
  • I've updated the answer
    – Bilfred
    Commented Nov 21, 2015 at 3:51

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