Re: severe hardlink bug

[C Anthony Risinger <anthony@xtfx.me>]

On Mon, Jul 30, 2012 at 4:36 AM, Arnd Hannemann <arnd@arndnet.de> wrote:
> Am 29.07.2012 21:13, schrieb C Anthony Risinger:
>> On Sun, Jul 29, 2012 at 2:02 PM, Konstantin Dmitriev
>> <ksee.zelgadis@gmail.com> wrote:
>>> Dipl.-Ing. Michael Niederle <mniederle <at> gmx.at> writes:
>>>
>>>> I reinstalled over 700 packages - plt-scheme beeing the only one failing due to
>>>> the btrfs link restriction.
>>>>
>>>
>>> I have hit the same issue - tried to run BackupPC with a pool on btrfs
>>> filesystem. After some time the error of "too many links (31)" appeared to me.
>>> Now I'm forced to migrate to some other filesystem...
>>
>> btrfs only fails when you have hundreds of hardlinks to the same file
>> in the *same* directory ... certainly not a standard use case.
>
> Actually, "hundreds of hardlinks" is certainly over optimistic.
> In my testing 15 links in the same directory were enough to get
> the "Too many links" error. It depends on the length of the file
> name of the hardlinks.

Yes, per the linked patch it states 4k as the limit ... I thought I
recalled a limit of 256 but it seems I may have been mistaken.

The purpose of my initial response was to suggest an alternative
strategy -- one complementing btrfs's strengths -- a simple rsync +
snapshot is much more effective than BackupPC IMO ... but then again,
I'm bias, because I generally think BackupPC is junk.

--

C Anthony