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JamesMuir

Using USB drives before shucking them

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The problem I have is the WD elements drives I plan to shuck will arrive on Sunday to my home address where the server will be but I go back to uni halls on the Monday morning in time for a 1am lecture. I want to preclear the drives before I shuck them. Can I add them to the array whilst there still in the enclosure before I shuck them when I'm next home for the weekend without losing any data on them.

Thanks,

James 

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USB connections in the array, though allowed, are NOT recommended due to unreliability.

 

You say "preclear". Preclear is not done with a disk in the array. Perhaps you meant "clear" instead.

 

You can test a drive using the manufacturer's software which is free for download.

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I mean preclear before adding them to an array via USB and then add them to the array whilst still connected via USB, so I can start transferring data onto the drives before I'm back home and can shuck them. Will the data still be usable if they are in the array via USB before I then shuck them and connect them via sata. Sorry.

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Just now, JamesMuir said:

Will the data still be usable if they are in the array via USB before I then shuck them and connect them via sata.

Depends on whether you are lucky and the USB connections don't get dropped. If they do, then your whole array will be down or at least have no redundancy due to missing disks.

 

The only way I would consider running with USB connections in the array is if I had decided to not use a parity disk for some reason, such as only storing very unimportant data. Once you drop a disk in an array with parity then you have problems you need to address immediately.

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So provided the USB connection does't get dropped I can just shuck them later, connect them via sata and all my data will still be there and the parity  drive will work. I only plan to run it like that for 2 weeks because I won't have time to preclear the drives via USB before I head back to uni.

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And it is possible that Unraid won't recognize the disks after they are shucked. It is even possible that they won't mount due to the way some USB enclosure interface to the disks.

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Okay thanks for your help, I'll refrain from adding data to the drives and just set up the docks on the cache but add the drives so the array will start and then reformat everything later.

Edited by JamesMuir
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3 minutes ago, JamesMuir said:

Okay thanks for your help, I'll refrain from adding data to the drives and just set up the docks on the cache but add the drives so the array will start and then reformat everything later.

Not really following you there. I also don't recommend USB disks in the cache pool if that's what you mean. Dropped disks there are bad too.

 

You don't have to "preclear" any disks. The only purpose of preclear these days is to test a disk, and perhaps burn it in a little to get it past "infant mortality".

 

Unraid will clear a disk if it isn't already clear when you add it to a new slot in the array. Much older versions of Unraid this clearing took the array offline until it was done, so preclear was invented to clear a disk before (pre) adding it to the array.

 

And Unraid only requires a clear disk when adding it to a new slot in the array. It is not needed when replacing a disk, whether for failure or simply for upsizing, since the entire disk will be overwritten anyway. Clearing a disk is strictly for the purpose of keeping parity valid when adding a disk to a new slot, since a disk that is all zeros has no effect on parity.

 

As I said before, you can test a disk using the manufacturer's software. As for burning it in, some do and some don't. It is probably less risk to simply use a new disk with SATA than to try to use it with USB simply because you have not had time to preclear it.

 

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Using them as Unassigned Devices is OK, and the usual way to use USB connections with your server. Of course, they won't be in User Shares that way so it is a little more trouble to use them for some things, but they will give some temporary capacity if you really need it.

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Thanks for your advice, and I don't plan to use the disks in the cache pool, I've got an SSD arriving tomorrow as well for that. And I need to set up storage this weekend because I've run out, so I need something set up quickly before I'm back at uni.

 

Edited by JamesMuir

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