TeraStation 2: adding usb hard disks for backups

We got one of these at work years ago as a backup unit, and it’s been working well. Exactly one disk error in years and it fixed itself, basically. However, as disks age you know they are going to fail, taking your data with it. So the only fix is to proactively replace them, and also run backups. I thought that it would be easy to add a backup disk, because there are USB ports on the terastation. That was not the case.

The first problem was that the disks weren’t writable. The TS supports reading but not writing to FAT32 and NTFS. It will read and write from XFS and Ext3. Since XFS isn’t solid on Linux AFAIK, I suspected that the Buffalo XFS is just tested to work against other Buffalo forks of the OS, and it’s not a usable format for backups. That leaves Ext3. While it’s not as good for backups as FAT32, it’s at least readable by a generic Linux system. (Backup disks must be readable on systems other than the one on which the backups were made.)

So, to format, you should use another computer, because the TeraStation cannot do anything else while it’s formatting a disk. Yes – the terastation won’t format a disk in the background. Formatting a 2TB disk from a Linux computer takes less than an hour. Here are the commands if the disk shows up as /dev/sdb1:

fdisk /dev/sdb1
[in fdisk] t
[in fdisk] 83
[in fdisk] w
mkfs.ext3 /dev/sdb1

Then wait.

I’m trying two types of formats. A 2TB partition in an Intel/MBR partition table, and a 3TB disk without any partition table.

The first try at the 2TB Intel/MBR failed because the partition type was W95, not Linux. I had to use FDISK to change the partition type to Linux. Then I had to reformat, and the disk eventually became visible to the terastation.

The 3TB without a partition table failed. I gave up on this one, because forum posts indicated that there’s a 2TB limit in the TS firmware, and it probably won’t go away.

I’m not sure about GPT partition table support in the TS.

Once the right format is in, the backups will work. The backups are dated rsync jobs, and the files are just copied as files, not in some archive format.