# Choosing a proper filesystem for a portable device

## pavallokazzo

Hi all,

I have this USB (ide to usb) box which contain a 250GB HD (ide) that I want to use as a portable storage device

What do you guys suggest me for filesystem?

Here some of my thougts regard this:

Ext3

- does not have "natural" winz compatibility

- is it good for recovering data????

- you got to properly dismount it to use under windows (www.fs-driver.org drivers)

- disk usage by filesystem (250GB HD is 213 GB file system   :Shocked:  )

reiserfs  -> NO!

- oh my god, no! it nearly destructed a my HD... in true, it just produced around 1gb (!!!) of badblocks dued by errotic magnetic writes... restore of the badblocks with hd' utility didn't worked, I had to blank it and now seems working good

- it doesn't have a real win compatibility at all

fat32

- works ok and is winz compatible

- defragmentation.........

- and file size limitation........

ntfs

- works and is winz compatible

- defragmentation

- you got to properly dismount it in order to use under linux

- compression on the filesystem (does work on ntfs-3g???)

Of course I want windows compatibility, but for ex. I could also use ext3 and put a little fat partition at the front containing fs-driver.org ext2 driver for windows... but ext eats more than 30 GB for its fs on my 250 gb hd... and I can't find any updated info about recovering data with ext3... everybody seems to suggest photorec... at least for the ntfs I can find thousands of programs of that kind...

right now I'm going to use ntfs, but I wish somebody can help me in maybe choosing something better!

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## NeddySeagoon

 *pavallokazzo wrote:*   

> but ext eats more than 30 GB for its fs on my 250 gb hd

 

Both ext2 ans ext3 reserve 5% for the superuser by defualt. thats 25G or so on a 250G filesystem.

You can safely recover that with tune2fs as long as you really don't want to write logs and lock files there.

ext3 == ext2 + journal.  All the ext2 tools work. However, I would avoid a journaled fs on USB.

Theres lots of anacdotal evidence of problems.

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## pavallokazzo

i didn't heard problems in using journaled fs on usb, however I don't see the needs...

also, thx for that tune2fs thing caused i didn't read anywhere about saving the space for superuser in ext family...

other than, that ext2 is well supported for data recovery, while seems some tools that works this way with ext2 filesystems can cause some damage on ext3 fs...

I think I will use ext2, trying to get some good tuning...

about that, can you help with something I have to know/put on tune2fs, some options that I could use for a storage device...

i think that most of the default option are for normal use (like this 5% reserved for the superuser... who needs on a usb hd?), what are the things I can work on?

thx

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## lyallp

I use FAT32 for my USB hard drives, my reasons are

1. It works on Windoze.

2. It works on Linux.

3. It works on Mac (well, it should, I don't have one to test it).

4. I can live with the file size limitation.

5. Provides an easy mechanism to move data between systems.

I don't have NTFS on my USB hard drives because I don't trust ntfs-3g (yet) - it did not work in some cases for me at one point. I do have some NTFS filesystems mounted locally, howeve, but generally use them read-only.

I use XFS, and have done for years, on my local disks but did not even consider a *nix filesystem that could not be read by Windoze.

If the USB case is only ever going to be plugged into your linux, then why not use a journaled filesystem (ext3 is just ext2 with journaling bolted on), but if there is any chance you will unplug it and put it into some other computer, stick with FAT32 - you can't even rely on some linux machines having ext3 available, I know mine doesn't.

Fragmentation, not even something I consider. It is way over-hyped, IMO. Particularly on modern machines with multiple processes/processors - a valid argument back in the days of DOS, no longer in todays multi-tasking OS's.

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## pathfinder

 *Quote:*   

> Both ext2 ans ext3 reserve 5% for the superuser by defualt. thats 25G or so on a 250G filesystem.

 

well, this is rather 10%  :Very Happy: 

Jokes apart:

ntfs is readable by linux with NTFS-3G. Works pretty well, though sometimes, won t write. I/O errors.

FAT32: I would DEFINITELY NOT use such a FS. Nor the NTFS one: not because of the file limitation (though depending on your data, it could be a serious limit), but becasue of the WINDOWS thing!!!! Remember: it WILL be vulnerable to viruses in windows, so your data might be in trouble.

Now, ext3: there are nice progs, running at boot in windows, modifying its kernel, in order for you to use the ext3 partition: iTunes will see the tracks, and you ll be able to wirte on them.

And GREAT tools to recover data. A lot, and great.

My question: is there a way for EXT3 being usable by OS X?

HFS+ : not sure it is readbale by windows, but it could be a solution

Reiserfs, etc: not consiedered for me.

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## lyallp

From my perspective, FAT32 is the way to go, everything can read/write it with no problems.

Viruses are a weak excuse to sacrifice portability. They are addressed by other means - virus scanners, suitable usage patterns, etc.

That said, it depends on the end use of the device. If it's only ever going to be plugged into one machine, then make it the native FS of the machine, whatever that is.

If it's going to be portable to other machines, choose the lowest common denominator - if all other machines are linux too, then whatever FS is common between them. If Windows is one of the target machines, then your choices are either NTFS or FAT32. My current view of ntfs-3g is that it's reliability is not quite there yet, so that only leaves FAT32.

I am not saying I think FAT32 is a good filesystem, but it's the only reliable common denominator, assuming sensible mounting/unmounting - no filesystem is going to be reliable if you simply turn off the usb device with no warning, particularly under linux. Some have journaling, but journaling is only applied to the fundamental filesystem structures, not to the file content itself, so relying on journaling to 'save' your data on an unexpected disconnect, is a fallacy.

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## djinnZ

Some info about HFS/HFS+ ?

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## pavallokazzo

 *pathfinder wrote:*   

> 
> 
> Now, ext3: there are nice progs, running at boot in windows, modifying its kernel, in order for you to use the ext3 partition: iTunes will see the tracks, and you ll be able to wirte on them.
> 
> And GREAT tools to recover data. A lot, and great.

 

can you tell me something more about ext3?

in particoular:

- let the kernel support ext series fs (never heard about, i know there are driver that can do that, but I'm not sure at what point they're loaded... but that's something interest me for other uses)

- what about iTunes...? didn't understand a word!

- what about tools to work on data recovery? a long google search give me one answer: photorec... at least with ntfs I can recover just some files, not the all partition

Even if it's a cpu killer fs (in linux) I'll stick with ntfs cause:

- my target machines are nix and winz... mac right now it's not my interest... for winz ntfs it's native, for nix at least read only will work

- i didn't get at all the virus-thing, but I think i understand... should be related to file permission... it sounds good anyway!

- size limitations is something I need (as I store the iso copies of my owned games...)

- size of the partition: right now i've maked an ntfs partition over an ext3 free one on a 150 gb disk and free space passed by the 140 gb of the ext3 to the 149 gb of the ntfs... 9gb! (6% more than ext)

- you can mount dir on ntfs in win xp (don't ask me why i want that!)

however I know it's a pain in speed and system load...

even on win xp, I've noticed alot of speed loss in trasferring data... with fs-driver.org ext2 drivers I use to get around 12-15 MB/s writing and 40-50 MB/s reading, with ntfs I get 9-10 MB/s writing 40 reading... however seems good if I just want to play...ergh... if I want to transfer some data...

so I'll be open to change the fs, if I can find something better! or if loose all my data dued to ntfs!

about defragmentation:

it's not something related to CPUs... it's about the way data is stored on the device...

with iso90xx (that one of dvd and cd) filesystem you got defragmentation around 0% cause all the file are placed in line: block after block after block till the file ends and starts the other one...

this way fat is horrible... it works in a FIFO way: the first data to come will be writted to the next free block, till blocks are finished so it will start from the front... so if you are going to fill an hd you will get no fragmentation, but if you for ex. fill the disk, then delete a file and put another one in you'll get a part of the file at the end and another part somewhere on the disk... imagine yourself what happens to a system fs, with swap file and browser cache excetera....

ntfs should works better, but defragmentation is still an issue...

so bottom line, i'm ok defragmentation it's not a great concern on a storage device, but you should anyway take care about it... just give it a defrag when your computer is idle isn't a bad idea, you will earn in disk response time and speed...

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## pathfinder

Hi, Sorry if I messed you up.

I meant

- in windows, to access EXT3 FS there are nice progs. One of them is called Ext2FSD or something like this (sorry, can t tell you now)

- for data recovery, exactly, you have photorec and testdisk, but you also have ddrescue (much better than dd). For data recovery in windows, personally, I use Easy Recovery Professional (I have the chance to have one in our company, and I can use it whenever I want).  I loved ddrescue and it worked really well. Then, for ext3, you have a lot of ext3progs to tune it, have a look at the man page.

 *Quote:*   

> [U] sys-fs/e2fsprogs
> 
>      Available versions:  1.40.3 ~1.40.3-r1 1.40.4 ~1.40.5-r1 1.40.6 ~1.40.8 {elibc_FreeBSD nls static}
> 
>      Installed versions:  1.40.4(21:47:06 02/03/0(nls -elibc_FreeBSD -static)
> ...

 

- about iTunes: I just meant that the annoying thing with ext3 is that iTunes won't find your music files in it. But when ext3 is mounted at boot in windows thanks to ext2fsd, iTunes can see all the files afterwards.

NTFS-3G as said before is not OK yet: sometimes, it won't write. I/O errors. So don't rely on it. What's more, it was pretty slow actually.

About the viruses: my only concern is that if you have sensible data, in FAT32, as soon as you plug it into the WRONG machine (and never forget an USB flash drive WILL be plugged almost everywhere with time), you might be infected, and if it is just infection, using the data in linux shouldn t be a problem, but sometimes, it could be data damaged by a bad virus. It s highly hypothetic provided you take care of your actions, but I don  t like having a fat32 USB disk. I use ext3, and you can always get the ext2fsd prog from the net, or from a usb drive, and then be able to see whatever you want in your partition.

That said, I don't know what happens to your ext3 data when a windows machine able to read and write on an ext3 FS is infected.

HTH

That's my opinion.

edit: I do have a fat32 20Gigs drive: I can t pass my 4.7Go DVDs ISO files from computer A to computer B with it, due to size limitation. This is annoying. Really. But don t consider ntfs, cause ntfs-3g is still slow and unreliable right now. IMHO

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## irgu

 *pathfinder wrote:*   

> 
> 
> NTFS-3G as said before is not OK yet: sometimes, it won't write. I/O errors. So don't rely on it. What's more, it was pretty slow actually.
> 
> 

 

Hmmm, I get 40-50 MB/sec read and write speed with the latest version NTFS-3G 1.2310 and the other filsystems are not better either. Actually ext3 is slower when writing huge files. 

The I/O problems are typical with the Seagate external USB drives as described at http://www.ntfs-3g.org/support.html#ioerror

It could be also that you're using the old and indeed slow NTFS 1.810 which was the default Gentoo version until very recently:

http://www.ntfs-3g.org/releases.html

http://packages.gentoo.org/package/ntfs3g

ext3 and reiserfs weren't reliable on Windows.

FAT is size limited, slow and not robust to the hardware errors like NTFS which has fault-tolerance support.

Thankfully NTFS(-3g) works fine, even on OS X and FreeBSD  :Smile: 

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