N3200PRO backup to external USB harddisk

Monday, May 23th, 2011 by hinrich


As it took me a while to figure it out, here is how I create my data backup using an external USB harddisk.

First of all, like many people I am confronted with a family environment that is dominated by Windows. That triggered the decision to format the harddisk in FAT32 and not in ext3 (I did not dare try NTFS as I am not sure how well the Linux version of the N3200PRO would support it). Advantage: if the NAS would completely fail, I could attach the USB harddisk to any of our Windows machines and immediately have access to the data.

Secondly, I decided to use rsync for making the backups. As a consequence of my chosen harddisk format there is no point using "-a" in rsync. I have also taken the gamble to invoke the parameter "--size-only" as I run the backup only once in a couple of months (that's the time saver of having a RAID 5 while I do not have any highly critical data). The resulting command for a given top level directory (in the example below I use the music directory which is mounted from iTunes on my Windows machine) is:

rsync -rvt --delete --progress --size-only /raid/Music /raid/USBHDD/usb4/1/

Two more comments: I have intentionally chosen to not use cron to run it. Yes, I need to remember to execute the command. But when I do run it, I know that I cannot mess up versions - a typical problem when using cron and no incremental backup. One more thing: I have read that occasionally the external harddisk gets mounted under usb5. I have not had this until now, but it is probably something to check.

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