External USB hard drives with UNRAID?


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Can Unraid be used with external USB hard drives ?  

 

 

I know softwares sometimes advance and upgrade so I am hoping the answer may now be yes for the latest version? 

 

I asked a few years ago and people were very negative on it.

 

Please let me know if this has changed. 

 

I don't have some monster server with 50 hard drive enclosures with advance enterprise level cables and such. I have a normal computer with USB hubs and a lot of external hard *USB) hard drives. 

 

DATA is DATA so why could this not work?  What does it matter if your connection is SATA or USB ? 

 

Thanks .

 

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Can you?  Yes.

Should you?  No.

 

Data is data.  And USB hasn't changed much since a few years ago.  The biggest issue is that USB is much more prone to temporarily drop out.  When it does this on drive in the array, it can cause all sorts of issues - Drive not available on the array, data corruption (if it happens during a write), etc.  It is just not worth the headache, and is counter to the reason you would build a parity protected server in the first place.

 

Look at my sig.  I'm not using any expensive, top end server gear.  Mostly recycled PC stuff and inexpensive hardware.  I'd shuck a few of those drives, and install them in your case.

Edited by ConnerVT
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7 hours ago, miogpsrocks said:

DATA is DATA so why could this not work?  What does it matter if your connection is SATA or USB ? 

 

Does your Windows box ever make the sound out of the blue that indicates a USB device was disconnected then reconnected for absolutely no reason? 

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8 hours ago, Squid said:

Does your Windows box ever make the sound out of the blue that indicates a USB device was disconnected then reconnected for absolutely no reason? 

 

I'm not sure. Maybe? 

 

Here is the thing. I am not using it for an enterprise application. Its like once in a while I might need to pullup a excel file or a video file. 

 

Its not like I am reading/ writing 24/7. I also use USB external drives in my computer for most everything things. 

Once the UNRAID server is made, it will be used for 99.9% reading not writing. 

 

I can connect all USB external drives to UPS battery backup as well as the unraid server itself. 

 

I can fit the drives I need with external USB. I can't fit some monster server type box even know that is more professional way of doing things. 

 

Unraid also allowed for a SSD solid state drive buffer right? Do you know if there is a setting that it can verify items are complete before deleting the file? 

 

I had a real RAID 5 nas device from a major company crash because I think the hard drive company hide the fact that it was using Shingled magnetic recording (SMR) and it caused problems with the RAID 5 writing. It was also using some new file system that I had not used before which maybe cause the perfect storm. I'm not exactly sure but in any event, I like the fact that with UNRAID you can recover the information from individuals drives if worst comes to worst. 

 

Despite the warnings  of USB, is it technically possible to add USB external drives in the UNRAID software? 

 

Thanks

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As I answered above, yes.  You can basically add anything that can be accessed as a drive (volume).  You could have a dozen freebee flash drives as an array if you wish.

 

The issue with USB is that devices tend to momentarily "drop out" and not respond when needed.  This is mostly due with the several layers of hardware and code between CPU and drive - drivers, hubs, USB to SATA translation.  In a Windows machine, this generally isn't an issue (unless it is your boot drive) as most of the time, it is "found" again as the system retries the request or the device finally sorts itself out. 

 

A SATA or SAS connected drive doesn't have nearly as much stuff between CPU and the drive.

 

In the Unraid array, these errors by the USB hardware are treated as a drive error.  In my opinion justifiable, as the reason for having a parity protected array is to trust your data's integrity.  If a drive drops out, the disk will likely be displayed as a failed disk, and data from it would be emulated by parity, until you take action to resolve.

 

USB drives can have a place in Unraid.  I have two connected to my sever as Unassigned Devices.  One is a external USB enclosure I use for off site backup (I have 2, and swap each month, taking the most recent to my office for safekeeping).  The other is a flash drive I keep plugged in the server, to quickly transfer some files then grab and go.

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9 hours ago, ConnerVT said:

As I answered above, yes.  You can basically add anything that can be accessed as a drive (volume).  You could have a dozen freebee flash drives as an array if you wish.

 

The issue with USB is that devices tend to momentarily "drop out" and not respond when needed.  This is mostly due with the several layers of hardware and code between CPU and drive - drivers, hubs, USB to SATA translation.  In a Windows machine, this generally isn't an issue (unless it is your boot drive) as most of the time, it is "found" again as the system retries the request or the device finally sorts itself out. 

 

A SATA or SAS connected drive doesn't have nearly as much stuff between CPU and the drive.

 

In the Unraid array, these errors by the USB hardware are treated as a drive error.  In my opinion justifiable, as the reason for having a parity protected array is to trust your data's integrity.  If a drive drops out, the disk will likely be displayed as a failed disk, and data from it would be emulated by parity, until you take action to resolve.

 

USB drives can have a place in Unraid.  I have two connected to my sever as Unassigned Devices.  One is a external USB enclosure I use for off site backup (I have 2, and swap each month, taking the most recent to my office for safekeeping).  The other is a flash drive I keep plugged in the server, to quickly transfer some files then grab and go.

 

SAME issue caused problem with SMR hard drives stalling the writing process with internal drives in my normal RAID system .

 

Does Unraid have the ability to extent the time to live ( TTL) value so it won't be so quick to mark a hard drive as dead? 

 

Seem like that would solve a lot of issues.  Give the drive a chance to respond .

 

Its sort of like calling customer support and the agent disconnect the call because you took a few milliseconds too long to respond to them. 

 

Thanks .

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I have not heard of any instance where SMR drives have caused issues with Unraid.  Maybe the slightest of performance issues, but something only seen if searching hard for it.  Unraid is not designed for speed.  There are other RAID setups which cater to those looking for the fastest transfer rate.

 

Your customer support analogy is faulty.  The issue isn't that there is a delay in response.  Here there is a loss of communication between the system and the drive's controller.  So it would be, in your analogy, the CS representative hearing a loud click and then a dial tone.

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