Best NAS OS / config for storage server, 8x2TB HDDs?

[poofyhairguy]

Using this as a guide for RAID-4/Unraid:

https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_4
http://lime-technology.com/wiki/index.php/UnRAID_Manual_6#Add_One_or_More_New_Disks

Wouldn't it be impossible to stream the data off a single drive (and powering down all other drives), as RAID-4 is block level striping with a dedicated parity drive?

Unraid is basically non-striped RAID 4. So you can just use one disk at a time. That is basically what makes it so great for media server use (where the media file is only on one disk at a time). The trade off is write speeds are slower than a single drive.

Also your example of adding a 3TB drive to an array of 1.5/2TB drives seems inaccurate. As the parity drive must always be the largest. So if you only add a single 3TB drive in that example, you'd net no usable disk space.

Yeah as I said your parity drive has to be the biggest drive. The magic is you can upgrade the non-parity drives one at a time rather than having to buy either the exact same sized disk to grow the array (like normal Linux software raid) or having to buy an entire new pool of disks and migrate the data over manually (most hardware RAID and zfs).

 

[grimpr]

Using this as a guide for RAID-4/Unraid:

https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_4
http://lime-technology.com/wiki/index.php/UnRAID_Manual_6#Add_One_or_More_New_Disks

Wouldn't it be impossible to stream the data off a single drive (and powering down all other drives), as RAID-4 is block level striping with a dedicated parity drive? So at best you'd be powering up n-1 drives instead of n drives for RAID-5/6. From what I gather, and the same recommendation goes on the FreeNAS forums, powering up and down drives (or head parking) is much more stressful than actually running a drive 24/7. They actually recommend disabling it or setting the parking timeout to 5 minutes.

Also your example of adding a 3TB drive to an array of 1.5/2TB drives seems inaccurate. As the parity drive must always be the largest. So if you only add a single 3TB drive in that example, you'd net no usable disk space.

I agree 100%, parking drives is harmful to the drives health due to material physics involved.

 

[PingSpike]

poofyhairguy pretty much went over it. Its not RAID4. Everyone and their brother recommends freeNAS ZFS but it always seemed like the totally wrong solution for a home media server to me. Its to restrictive with disk selection which makes it expensive and to cumbersome for home use IMO. A great solution for enterprise that somehow is really popular for home use. unraid lets you take a pile of old mismatched drives you have lying around and essentially squish them together (there are some minor limitations) into one big array with a single parity disk (they've been working on dual parity though) to provide some level of protection for single drive failures. It comes with an easy to use web UI. That's pretty much all I wanted.

You can turn off parking altogether if you want and the drives can suck power all day while idle and not doing anything if you desire.

I know, I know...it doesn't do all that amazing stuff that ZFS can do. And it can do some amazing stuff. But I didn't really need any of that for my purposes.

 

[PingSpike]

SnapRAID is another option that is of interest by the way. There's a plug in for OMV that removes a lot of the setup pain too.

 

[poofyhairguy]

I agree 100%, parking drives is harmful to the drives health due to material physics involved.

I have had multiple consumer drives give me 5+ years of runtime with no issues in Unraid. I set drive parking to a high value (I think like three hours), and it works fine. Hell I have had drives that Backblaze had problems with work fine for 5+ years in Unraid. Parked drives can work if you are conservative.

Here is a pretty good compare page to compare options:

http://www.snapraid.it/compare