A faster and easier way to make LUN files for your SCST SAN

I've been writing a lot lately about SCST iSCSI SANs again. It's been a few years since I've had a chance to configure one of these from scratch, and a lot has changed since 2012 when I first started using these.

In the past I've always used dd to create LUN files for use with SCST. For thin provisioned LUNs I would run something like the following:

sudo dd if=/dev/zero of=lun1 bs=1 count=0 seek=1T

For thick provisioned LUNs I would run this instead:

 sudo sudo dd if=/dev/zero of=lun1 bs=1024 count=1T seek=1T

Well, I found two utilities that do the same thing, but they are way faster and the syntax is way easier! One is called fallocate and the other is called truncate!

To create a thick provisioned LUN, you would use fallocate to create your file by running:

sudo fallocate -l 1T lun1

To create a thin provisioned LUN, you would use truncate to create your file by running:

truncate -s 1T lun1

So simple right? Why am I just learning about this now!?