Will unRAID use multiple HBAs to increase bandwith for RAID 5?


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I plan on making a NAS with 8 drives in RAID 5. This will give me a significant increase in performance, my HBA card however only supports 6Gbps which would be a bottle neck. My question is, would unRAID be able to utilize two HBAs with 6Gbps to increase the total bandwidth? I have a google spread sheet of the individual parts here.

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unRaid isn't raid.  There is no striping involved across the disks.  While you can have 1 or 2 parity drives, each data drive contains it's own filesystem, and you are limited in access speed by the speed of the drives.

 

Setting up a cache pool however, you can choose multiple RAID levels, in which case you can max out your bandwidth because it will be striped.

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5 minutes ago, Squid said:

unRaid isn't raid.  There is no striping involved across the disks.  While you can have 1 or 2 parity drives, each data drive contains it's own filesystem, and you are limited in access speed by the speed of the drives.

 

Setting up a cache pool however, you can choose multiple RAID levels, in which case you can max out your bandwidth because it will be striped.

I'm confused, LinusTechTips has done many videos with unRAID even being sponsored, and he always used RAID. In this video he even suggests using unRAID on the NAS. I feel like I'm looking at the wrong software.

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5 minutes ago, diamondpumpkin said:

I'm confused, LinusTechTips has done many videos with unRAID even being sponsored, and he always used RAID. In this video he even suggests using unRAID on the NAS. I feel like I'm looking at the wrong software.

if you want true raid, yes, wrong software. There is parity protection, but no stripes on the array. Which is actually nice because if the array tanks, you have a much higher ability to recover data. It's the primary reason I use it.

Edited by 1812
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UnRAID does not use any of the standard RAID techniques.     It has some similarities in that it has parity protected data but it functions in significantly different manner (hence it's name).   

 

The differences make it very suitable for many home users, but one thing you should not be expecting is anything special in the way of performance.

Edited by itimpi
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Wrong. It has more interesting feature than the free stuff.

 

The ability to not loose all your data if multiple drives die. You lose two drives in RAID5 and you lost 100% data. You lose 3 drives in RAID6 and you lost 100% data. You lose 2 drives in a 10 drive unRaiid (1 parity) and you still retain the data on all 8 other drives, if your lucky and a lost drive is parity you then have data of all 9 other data drives.

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Also more power efficient.  Unlike a RAID system, with unRaid not every drive has to be spun up in order to read a single byte from one file.  Only the drive that has the file has to be spinning.

 

Additionally, a URE will not cause the array to have to go through a rebuild, ability to use mismatched drive sizes and retain the full size of all of the drives, far far easier (and cheaper) to expand the array incrementally.

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21 minutes ago, diamondpumpkin said:

Didn't think I would have to pay for software with less features than the free stuff. My bad.

Such attitude.  Let me simplify it for you.

 

Unraid is a horse.

You come to the forum asking if having 2 milking machines will help make it faster and then, after being told a horse is a not a cow, you lament that you would have to pay for a horse with less features than a free cow.

 

Make sense?

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unraid's "array" is closer to RAID 3 than anything.

 

This does allow for easier data recovery and more power savings... for smaller amounts of data, like at home, this is great. It allows for adding drives of dissimilar size, which for most of us home users is really great too.  However, this SEVERELY limits the IOPS (due to single disks handling parity and not striping it).  You will never be faster than the slowest, single drive in your "array"

 

I was pretty skeptical, but it is pretty great for home use for general use.  My "array" drives are all enterprise class 7200 rpm NL drives with 128MB cache.  They are all matched.  The maximum transfer I can get in regular mode is about 52MB/s, in turbo mode is about 102MB's.  That's really pretty bad compared to RAID.  That cache pool is a bandaid to make up for these limitations, and works fine.  It saves power too.  I would suggest never running a VM from this array, as it really runs like crap.... but if you run VM's from a BTRFS pool, it runs good.

 

You have to weigh the pros and cons.  I have a larger, dual xeon server too with 8 drives on a caching controller, but it sucks down all kinds of power, generates heat and makes a great deal of noise.  It runs ESXi, and is great when I'm labbing things... but I wanted to stop running it all the time.  My new unraid box is an mITX i3 that runs most of the time with none or one drive spun up. and is dead silent, and pulls about 28W on average.  The wife approval factor is significantly higher on the unraid box running 24/7 :)

 

If you want something with a more traditional setup and to run as a NAS with a pretty web interface, I'd suggest Open Media Vault (OMV) as it's based on Debian, supports dockers and VM, btrfs, ZFS, XFS EXT4 and whatever else  and runs well.  You could also run snapraid with mergefs on it to get a similar experience to unraid in being able to tack together dissimilar drives, albeit with delayed parity updates.  Also, it's FOSS and free to use.

Edited by Abzstrak
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