Re: Recommendation for filesystem for USB external drive for backups
On Fri 14 Aug 2020 at 08:25:20 (+0300), Andrei POPESCU wrote:
> On Mi, 12 aug 20, 20:14:03, rhkramer@gmail.com wrote:
> > I'm getting closer to setting up a consistent backup plan, backing up to an
> > external USB drive. I'm wondering about a reasonable filesystem to use, I
> > think I want to stay in the ext2/3/4 family, and I'm wondering if there is any
> > good reason to use anything beyond ext2?
>
> In my opinion using ext2 in 2020 is mostly pointless, beyond the rare
> situation where some software doesn't support ext4 (e.g. some odd/old
> bootloader, other OSs, etc.).
>
> Because it is getting significantly less use support for it is also more
> likely to bit rot.
>
> As far as I know ext3 is mostly ext2 with journalling added.
>
> In comparison ext4 was developed from scratch with journaling and
> support for other newer techniques, like better allocation of space to
> prevent fragmentation and improve performance.
If you create your backup partitions on a newer distribution,
just check that wheezy can mount it before you start filling
it up. There are one of two options that wheezy kernels can't handle
in ext4, though I don't know whether any of them get enabled by
default. man ext4 for details.
Ditto for any encryption scheme you might use.
> > (Some day I'll try ZFS or BTRFS for my "system" filesystems, but don't see any
> > point (and don't want to learn) either of them at this point -- I don't see
> > much need for a backup filesystem.)
>
> As has been stated already, both btrfs and ZFS have built-in bitrot
> protections that are very useful for backups and archives. To achieve
> the same level of protection on ext4 you need additional tools.
I'm dubious whether I shall ever start using these filesystems.
I create multiple backups on ext4 filesystems on LUKS, and keep
MD5 digests of their contents. Would that qualify as your
"additional tools"?
Cheers,
David.
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