It is usually quicker to just zero the disk instead of random bytes, just because the randomness pool might be scarce in a system. This can save hours when clea

It is usually quicker to just zero the disk instead of random bytes, just because the randomness pool might be scarce in a system. This can save hours when clearing a large and fast disk, like a SSD. /dev/zero usually has much more throughput than /dev/random. Of course this matters less on slow disks, where the bottleneck is the writing speeds anyway.