Re: Can BTRFS handle XATTRs larger than 4K?

[Austin S Hemmelgarn <ahferroin7@gmail.com>]

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On 2014-12-22 12:27, Richard Sharpe wrote:
> On Mon, Dec 22, 2014 at 6:28 AM, Austin S Hemmelgarn
> <ahferroin7@gmail.com> wrote:
>> On 2014-12-19 21:07, Richard Sharpe wrote:
>>>
>>> Hi folks,
>>>
>>> I need a Linux file system that supports XATTRs up to 64K.
>>>
>>> Can BTRFS support that or is XFS the only Linux file system with such
>>> support?
>>>
>> At the moment, BTRFS is limited to xattrs that fit inline in the metadata
>> nodes (so ~3900 bytes for a 4k leafsize).
>>
>> XFS, however, isn't the only Linux filesystem that supports xattrs that
>> size.  Assuming that you are using a recent kernel, you can also use such
>> xattrs on at least:
>>   * XFS
>>   * JFS
>>   * ext4
>>   * reiserfs (I think, not 100% certain about this one though)
>>   * OCFS2 (even though it is technically a cluster fs, it can be run single
>> node without the clustering)
>>   * ZFS (IIRC, ZFS supports unlimited xattr size)
>>   * NTFS (no limit on xattr size, though you should use NTFS-3G instead of
>> the in-kernel driver)
>>   * SquashFS (read-only)
>>   * HFS+ (Also no limit on xattr size)
>> Of these, I'd personally suggest using XFS unless you need to be able to
>> shrink the filesystem, in which case I'd suggest ext4.
>
> Thanks for the info. I hadn't realized that ext4 had lifted the restriction.
>
Yeah, it would be nice if there was more clarity in the documentation.

Personally, I'd love to see unlimited length xattr's like NTFS and HFS+ 
do, as that would greatly improve interoperability (both Windows and OS 
X use xattrs, although they call them 'alternative data streams' and 
'forks' respectively), and provide a higher likelihood that xattrs would 
start getting used more.


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