Time Machine running on Linksys WRT600n with external drive.

Question

Hey Folks,
After searching the internet for the answer on how to setup OS X Time Machine on my Linksys WRT600n with storage link, and finding nothing or only parts of what I needed, I finally got it to work. Hopefully this will help you in your setup.(this should work for any linksys routers with storage link.)
1) First you will need to attach your external USB drive to the Linksys Router, and format it using the linksys utility. This will format the drive as fat32 so it can be access by the mac and the router.
2) You now need to create a share on the drive using the Linksys utility (I called mine "TimeMachine") and grant R&W permission to it. I found and article that said you have to create a group called "root" and a user called "root" within that group, then grant the group R&W access to you share. I did this but I am not sure if its required. you may be able to edit the default "admin" account.
3) Once you have the share created you should be able to access the share from your mac by logging into it using your (Linksys) "root" account and password. Make sure you can save a file here. You maybe able to create a folder but make sure you can save a file (.doc for example).
4) Apple has blocked the use of unsupported drives in Time machine so you will have to make a change for this to work. open a terminal window and type the following in one line:
defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
Hit enter, and close terminal.
5) For some reason Time Machine will have issues creating the .sparse bundle Disk required for the backup over the network. So you will have to create it yourself. Safely unplug the USB drive from the router and plug it into your mac. Open disk utility (applications > utilities > disk utility) and create one the same size as your external drive.
parameters:
- Volume name: "Time Machine" (has to be this to work)
- Mac OS Extended (Journaled);
- No partition map
- sparse bundle disk image
Make sure the sparse bundle is in the share folder. If Time Machine had created this sparse bundle it would named it after your machine. You will have to rename it accordingly. This is the required format 'computername'_'mac address without colons'.sparsebundle
(eg. "joe's MacBook Pro_000000000000.sparsebundle")
6) Once all the above is complete you can reattach the drive to the router, and attach to the share again from your mac. Open Time Machine and you should see your share. Setup Time Machine to use this drive. You may want to be connected using Ethernet for the first backup as it may take a while.
I have found the wireless backup to take a bit of time to prepare and run but it seams to work nonetheless. The slowness could be caused by the difference in mac addresses from wired to wireless. So you may want to change the sparse bundle file name depending on how you are accessing time machine.
Hopefully this will work for you as it did for me.

Answer 1

I am afraid I have to pour some cold water on your enthusiasm.
Yes, what you say can get TimeMachine working, but there is a nasty snag:
WRT600N uses FAT32 for its external harddrives and (regretably) understands nothing else. FAT32 has two restrictions:
1) Maximum file size is 4GB
2) (a lesser-known one) Maximum number of files in a directory of 65,535.
The first restriction isn't really a problem because Time Machine organizes its data in 8MB "bands", which are files within your sparsebundle directory.
The second restriction, however, will cause Time Machine to eventually hit a brick wall: The sparsebundle bands are given a sequence number in hexadecimal and there isn't really a limit to how many you can have. If you run Time Machine on a large harddrive attached to the WRT600N, you will eventually run into a situation where you are hitting the 65,535-files-in-a-directory limit. Time Machine will, therefore, run for a while and then suddenly fail for no apparent reason.
Given the parameters of Time Machine, you can't run Time Machine reliably on a WRT600N with an external harddrive larger than 8MB * 65535 = 512GB. If that's good enough for you, then great. If not, you can do one of two things:
1) Get something that doesn't format its harddrive in FAT32. 
2) Install DD-WRT on your router (thus voiding its warranty), fight with it for a while in order to get SAMBA running on it, and gain the ability to format your harddrive in Ext2.
 I hope this helps somebody.