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Best Filesystem For External Back-Up Drives?
rufey writes "I've recently embarked on a project to rip my DVD and CD collection to a pair of external USB drives. One drive will be used on a daily basis to access the rips of music and DVDs, as well as store backups of all of my other data. The second drive will be a copy of the first drive, to be synced up on a monthly basis and kept at a different location. The USB drives that I purchased for this are 1 TB in size and came pre-formatted with FAT32. While I can access this filesystem from all of my Windows and Linux machines, there are some limitations." Read on for the rest, and offer your advice on the best filesystem for this application.
"Namely, the file size on a FAT32 filesystem is limited to 4GB (4GB less 1 byte to be technical). I have some files that are well over that size that I want to store, mostly raw DVD video. I'll primarily be using these drives on a Linux-based system, and initially, with a Western Digital Live TV media player. I can access a EXT3 filesystem from both of these, and I'm thinking about reformatting to EXT3. But on Windows, it requires a 3rd party driver to access the EXT3 filesystem. NTFS is an option, but the Linux kernel NTFS drivers (according to the kernel build documentation) only have limited NTFS write support, only being safe to overwrite existing files without changing the file size). The Linux-NTFS project may be able to mitigate my NTFS concerns for Linux, but I haven't had enough experience with it to feel comfortable. At some point I'd like whatever filesystem I use to be accessible to Apple's OS X. With those constraints in mind, which filesystem would be the best to use? I realize that there will always be some compatibility problems with whatever I end up with. But I'd like to minimize these issues by using a filesystem that has the best multi-OS support for both reading and writing, while at the same time supporting large files."
Thats exactly what I did. Threw a couple of external drives on a Mac Mini. Formatted as HFS+ and did software array. Then using afp and smb provided the contents as shares to the Windows media center and various client machines on the network.
Sure, software raid over USB is slow, but the bottleneck is the network so it doesn't really matter.
I'm out of my mind right now, but feel free to leave a message.....
I personally go the other way. Sure, there's an Ext3 driver for windows, but from what I've seen it's not that good. On the other hand, I've used the NTFS driver on Linux quite a bit and it's worked pretty well. More importantly, I have confidence that the NTFS driver will continue to get better.
Honestly, if FAT32 won't do what you need, NTFS is pretty much where you'll need to go. NTFS-3g gives you stable read/write capability on Linux and OS X as a FUSE driver; in fact, many distributions have NTFS-3g in their repositories. There's also native NTFS write support in Snow Leopard if you want to risk turning it on. I personally haven't had any issues with it, but some people have encountered file corruption when using it, so you might want to be wary. It is worth noting, however, that many embedded devices won't read anything other than FAT. If you plan on hooking this drive up to, say, a DVD player to show pictures, NTFS won't work for you.
Like it or not, Microsoft file systems are the lingua franca of file transfer on portable drives these days, merely due to the installed base of Windows computers.
The Freelance Wizard
I have ~6TB on external USB drives and I've been doing this for a few years now. I have a few words of caution about NTFS. If you get an USB drive that for example spins down or if you turn your USB drive off without properly dismounting it (or if Windows crashes), you might see this line:
Delayed write failed!
And on two occasions that meant that Windows fucked up the file allocation table or whatever it's called under NTFS and I lost the _entire_ disk.
Windows loves getting its fingers into that table whenever you mount a USB filesystem. It's not like it tries to keep its write cache empty. Nooo.. every file access needs to be continuously recorded in that thing.
Anyway, be careful when you use NTFS on a USB drive. Alternatively use EXT3, which you can still mount under Windows using:
http://www.ext2fsd.com/
(Note that these experiences are under Windows XP, I have no clue if Vista or 7 does any better, I assume not.)
WRONG!
Irregardless is not a proper English word. Its usage has *ALWAYS* irked me from when I was a small boy to now. To use common vernacular, it's a mashup of 'irrespective' (one negative; prefix) and regardless (also, one negative; suffix). 'Irregardless' is a double negative and is thusly illogical by construction and would only be understandable to people born in the U.S. since 1970, and those less literate in the U.S. prior to that.
On my words that aren't words list it's right up there with 'impactful'.
Which particular driver are you referring to? There are a few.
Personally, I use Ext2 IFS in Windows (it works for Ext3 too) and it is, hands-down, the stablest and best Ext2/3 Windows driver I've used. Every other one I've tried would have stability issues; with IFS I don't have to worry. (There's been precisely *one* time in pretty much years that the driver crashed on me, and that's when I was doing something weird and stupid; I don't remember what. But more importantly, it didn't do anything bad to the filesystem in that crash.)
Dear AP,
I was pondering with a very similiar problem two years ago, when I bought my first terabyte-class external USB hard drive to my home server (old 800 MHz Duron). I was thinking exactly like you are thinking now, and decided FAT-32 would be the way to go. MISTAKE. Four important things stand out, that I want you to read:
Okay, those are my four vocal points. They could be in any order, because all of them are equally important reasons NOT to choose FAT-32! As it happened, after using the 0.5TB drive for 6 months with FAT-32, I bought more space (a new drive). This time there was no question about the filesystem. I made a small, few-sector long 200 MB FAT-32 partition to the beginning of the drive and downloaded all the latest Win32 EXT2 drivers there from different vendors, just for the really unplausible situation that I would ever want to mount these drives in Windows. Then I just made the rest Ext3. And, I am REALLY satisfied with the decision! Ext3 just work so sparklingly faster and better with Linux than FAT-32 ever does. Since then I have bought one more drive and did the same 200MB + 1TB thing. I will probably never use these drives in Windows, but it gives me a warm feeling to the heart that there's always a way if I should, even if the computer doesn't have an Internet connection.
Oh, one thing I forgot to mention: get a file server! It makes your life so much easier. Nowadays I am running a desktop computer with a 60 GB SSD drive and no HDD at a
The fundamental problem lies in USB bridge chips which do not properly implement the cache management commands. Others have replied that you need to disable the write cache, and while that would be a solution, it is often impossible. Even with bridge chips that do support the cache disable command, some hard drives will not honor it anyway.
Most USB bridges simply lie about when data has been written, which makes it very difficult for a filesystem on top of it to make any guarantees. While it may not happen often, this can have disastrous results, as you have seen.
The copy on write nature of ZFS left it especially vulnerable to broken USB storage, and could easily leave you with a corrupted pool requiring manual intervention and a bit of luck to recover. Thankfully, the recent bits address this, and ZFS is now the only filesystem that I would trust on top of USB storage. Most other filesystems will survive without incident, but at the cost of some silent data corruption.