I've managed to fumble my way through the installation process with luks on lvm partitioned disk. However, when I boot the actual operating system it outputs this;
A password is required to access the /dev/mapper/lvm-lvroot volume:
Which is to be expected, but about half a second later it outputs this;
[ 2.44.11.32] sd 6:0:0:0: [sdd] No Caching mode page found
[ 2.44.11.61] sd 6:0:0:0: [sdd] Assume drive cache: write though
So I enter my password below that text and press enter and the cursor just sits there. Doesn't matter what else I type the console is just frozen. Is there something wrong with my SSD? I shredded it before installation to try to secure it further like the arch drive preperation wiki said. Have I screwed it up somehow?

You perhaps should not use shredder, since it will increase wear out of a ssd.

There is a possible solution on the Arch forums:
https://bbs.archlinux.org/viewtopic.php?id=183980

...which deals specifically with LVM's and rebooting. From what I've read, it focuses around the /dev/mapper, and having to run cryptsetup from rescue mode first. The thread was solved, but the answer is a bit hard to follow.

---------- Post added 02-20-15 at 12:44 PM ----------

...which has ABSOLUTELY NOTHING to do with the OP's question, and is only really an issue if they do it ALL THE TIME, rather than once at build-time. Please, again, try to focus on the OP's question and post what's relevant to it.

That thread is pretty hard to follow, but from what parts I could catch from the dozens of different irrelevant issues was that the submitter was having problems with the boot loader not even asking for the password. My boot loader asks for the password, it just doesn't accept it when I input it. When I type it it just remains in plain text and when I hit enter it doesn't do anything.

On another note, I've fixed the other issue with the caching. It was due to the archiso usb stick. I was seriously too tired last night to even realize that it said sdd and not ssd lol. Anyway, taking the stick out fixed that however it did not fix the problem that the password seems to not be inputting at all when I type it.

I'm pretty new to systemd, so I don't know what all it does automagically, but I had a similar experience in the past. the solution was adding keyboard mods to my initial ramdisk. idk if that will help you but hopefully you get it figured out.

edit: yeah, if that's the problem you just boot up your install media, mount all your partitions, edit /etc/mkinitcpio.conf to include the keyboard module and make a new one.