FYI (large devices = looooonnngg processing times)

[Bill McGonigle]

On 04/27/2013 08:06 PM, Curt Howland wrote:
 > dd if=/dev/random of=/dev/sdb or whatever it
 > was, USB3.
 >
 > 6 days later

You might have just run out of entropy on the PRNG.  That and small 
writes will kill you.  Try:

   dd if=/dev/urandom of=/dev/sdX bs=2M

next time.  It should finish in several hours.  A 20TB ZFS array will be 
done in less than a day (the compression ratio is wonderful with 
/dev/zero...).  That and a scrub will let you know which disks got 
dropping in shipping.

-Bill

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