Re: ERROR: scrubbing <dev> failed for device id 1: ret=-1, errno=28 (No space left on device)

[Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>]

Henk Slager wrote...

> you need to do some balancing, as I think that the free space is too
> fragmented and the system fails to allocate extra metadata space
> needed for scrub doing writes into metadata.
> 
> # btrfs balance start -dusage=<number>
> with number somewhere between 5 and 50; first start with lower number
> and repeat and increase until the 5.17GiB gets closer down to the
> 3.75GiB

Thanks, that one worked with number 100. Still some ENOSPC errors but
appeareantly good enough to make scrubbing work.

> The issue is that for for a filesystem of this size (6.5GiB), it would
> have been better to have mixed data/metadata allocation. See help of
> mkfs.btrfs. So maybe you want to recreate the fs like that, otherwise
> you might easily hit this problem again if you don't monitor free
> space / balance regularly.

Will keep that in mind. Just out of curiousity: Initially, the file
system size was just 4 Gibyte. Is it possible this made things worse?


Oh, and by the way:

--- a/Documentation/mkfs.btrfs.asciidoc
+++ b/Documentation/mkfs.btrfs.asciidoc
@@ -77,7 +77,7 @@ where the space is reserved for the other block group type, is not available for
 allocation and can lead to ENOSPC state.
 +
 The recommended size for the mixed mode is for filesystems less than 1GiB. The
-soft recommendation is to use it for filesystems smaller than 5GiB. Thie mixed
+soft recommendation is to use it for filesystems smaller than 5GiB. The mixed
 mode may lead to degraded performance on larger filesystems, but is otherwise
 usable, even on multiple devices.
 +


    Christoph