On Mon, Feb 06, 2023 at 05:29:14PM +0100, Gabriel Niebler wrote: > Am 06.02.23 um 15:52 schrieb Zorro Lang: > > On Tue, Jan 31, 2023 at 01:38:39PM +0100, Gabriel Niebler wrote: > > > Signed-off-by: Gabriel Niebler <gniebler@xxxxxxxx> > > > --- > > > README | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/README b/README > > > index 008d3875..574cdd34 100644 > > > --- a/README > > > +++ b/README > > > @@ -127,7 +127,7 @@ Setup Environment > > > - device contents will be destroyed. > > > 4. (optional) Create SCRATCH device pool. > > > - - needed for BTRFS testing > > > + - needed for BTRFS testing (some tests require up to 5 disks of 10GB each) > > > > Not sure about this part, so btrfs recommend 5 disks of 10GB each in > > SCRATCH_DEV_POOL, to run all btrfs related tests? Does anyone know that? > > Or can you provide the subcase names which need "5 disks of 10GB each", > > to help to check and review? > > Of course (and thanks for asking, as it turns out my recollection was > slightly wrong on that one): > > To begin with, btrfs/011[1] states the "5 disks" requirement in the lengthy > comment at the top of the file: > """ > # The amount of tests done depends on the number of devices in the > # SCRATCH_DEV_POOL. For full test coverage, at least 5 devices should > # be available (e.g. 5 partitions). > "" > ... but it doesn't say anything about device size. > > btrfs/027[2] however checks the presence of 5 devices in $SCRATCH_DEV_POOL > directly in code and also runs a check to ensure that all of these devices > are *of the same size*. > > And then there are at least two tests that require $SCRATCH_DEV to be 10GB > or more in size: > - btrfs/079[3], which writes a 10G file to $SCRATCH_MNT and > - btrfs/253[4], which directly creates a 10G FS on $SCRATCH_DEV. > > *Taken together*, this means that for full btrfs test coverage, one needs a > $SCRATCH_DEV_POOL with at least 5 devices of equal size in it and that size > has to be at least 10GB. > > But that makes the remark wrong, strictly speaking, as there's no single > test that requires "at least 5 devices of 10GB each". > > How about this: "(for full btrfs test coverage, use at least 5 devices of > equal size and at least 10GB)" Even for now 10GB is enough, but we can't always assue that. There's not a clear restriction about that. I think we can skip this sub-patch. At least we don't give others a recommendation which isn't assured by ourselves. So how about only merge the 1st patch. > > > P.S. I'm thinking about if this "(...)" should be moved to below item. > > vvvvv > > > - specifies 3 or more independent SCRATCH devices via the SCRATCH_DEV_POOL > > > variable e.g SCRATCH_DEV_POOL="/dev/sda /dev/sdb /dev/sdc" > > Fine by me! :-) > > [1]: https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/tests/btrfs/011#n10 > [2]: https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/tests/btrfs/027#n20 > [3]: https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/tests/btrfs/079#n44 > [4]: https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/tests/btrfs/253#n90 >
