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I don't care about compatability or speed; I just want stability, that it is quick to respond, won't wrestle with me when I need to unmount it, etc.

Ext4, btrfs, xfs, or what?

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  • Are you talking about a live media USB? Those need to be FAT.
    – ubfan1
    Oct 6, 2014 at 1:01
  • Ive mounted ext4 disks before.
    – Anon
    Oct 6, 2014 at 1:51
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    Live USB disks do not need to be FAT. I don't know what you mean by Live Media USB though. Oct 6, 2014 at 2:23
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    Live media is the install media, which is created by the Startup Disk Creator. Gotta be FAT since it has to boot on UEFI machines. A full install to a USB can be ext4 (and you can turn off journaling).
    – ubfan1
    Oct 6, 2014 at 2:41

1 Answer 1

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When it comes to creating a startup disk from scratch (you want to add all files manually) I'd recommend Ext4, as it basically eliminates all the defrag stuff you need with FAT, it is simple and recognized by most everything UNIX, and has great error recovery support. If you are burning an ISO to create a LiveUSB then it would come with its own (FAT? comment and tell me if I'm wrong on this) format on the disk with an MBR or EFI partition. When it comes to an install disk, it really doesn't matter all that much so long as you don't have it set up to have persistent data across reboots, however if you are installing to the USB Ext4 is what I'd choose, just because in my experiences data integrity is pretty much assured in Ext4 so long as you don't have an unstable medium. in which case it fails completely as it spreads files all over the partition so you can't rely on just partitioning around it and having the free partition space line up with the error.

When it comes to speed and such, I'd refer here as the technology (NAND) is the same for USB drives and SSDs, even if the interface isn't. You may think that the difference in write speed between the two and the bottleneck from USB would limit the stuff here, but what this really measures is how fast a block of system data can be written, regardless of how much writing is actually going on (actually kind of finding how much data has to be put through the port to write a specific amount of data) : http://www.phoronix.com/scan.php?page=article&item=linux_315_hddfs&num=3

I haven't had a ton of experiences with btrfs, though really Ext4 seems like it would be stable enough to really outperform a lot of other filesystems and seems remarkably capable when compared with all (yes, all) filesystems used natively by windows, like FAT, NTFS, and FAT32.

If you are using it for constant writing on a missions critical machine, I would use XFS as Ext4 doesn't do complete metadata/logging of all files and their contents, however for normal use Ext4 is remarkably resilient and doesn't include any unnecessary write requirements for file verification. Once it logs the location of each file and maybe does a hash (on some systems) of a swath of data, it kind of just picks where to write to and does so without going through multiple layers of location verification for each block.

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  • Great answer, but you may want to not call an image for liveusb an "ISO". It is really a very bad misnomer that got stuck because the file system for optical media originally was ISO9660 (i think they now moved on to some other ones in addition to that). You won't use such filesystem for anything apart from optical.
    – v010dya
    Oct 6, 2014 at 5:44
  • AFAIK, ext4 isn't supported by all UNIX-like systems. Otherwise, excellent answer.
    – amanthethy
    Oct 12, 2014 at 21:48

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