XFS on Fedora i686, armv7hl

[Chris Murphy]

On Feb 28, 2014, at 10:02 PM, Orion Poplawski <orion at cora.nwra.com> wrote:

> On 02/27/2014 12:38 PM, Chris Murphy wrote:
>> 
>> On Feb 27, 2014, at 8:06 AM, Eric Sandeen <sandeen at sandeen.net> wrote:
>> 
>>> On 2/26/14, 11:37 PM, Chris Murphy wrote:
>>>> Hi,
>>>> 
>>>> Fedora is considering XFS as their default file system. They support
>>>> three primary architectures: x86_64, i686, and armv7hl.  Do XFS devs
>>>> have any reservations about XFS as a default file system on either
>>>> i686, or arm?
>>> 
>>> As Dave said, we rely on others to do ARM testing for the most part,
>>> though I've certainly jumped in and debugged some issues from time
>>> to time.
>>> 
>>> It'd be super if Fedora could run the xfstests test suite on arm
>>> as part of QE.  I'd be more than happy to help get that started
>>> if people are interested.
>> 
>> I don't know that Fedora QA has the resources to do this, but I'll cc the Fedora test@ (QA) arm@ lists. If these are highly automatable tests it might be possible, if they have the hardware. More likely I think it's that we need some ARM community folks to look at splitting up some of this work.
>> 
>> I'm not sure yet what concerns the ARM group might have with XFS either as this hasn't been decided, but the Fedora Server product working group is slightly leaning toward XFS by default. Performance and CPU hit wise on x86_64, XFS seems to match up well with ext4 and maybe even a bit better ratio of throughput/CPUtime for booting workload (systemd is parallel!) so if were the same on ARM XFS could work out slightly better for them.
>> 
>> 
>> Chris Murphy
>> 
> 
> I'm sure many people have much better info on this - but back in the
> day, running XFS on LVM (on md?) on i686 was not a good idea due to
> issues running out of stack space.  I don't know if this has changed in
> any way, or if arm is better in this regard.  But that would be my
> concern.  I think RHEL6 doesn't support xfs on i686, and RHEL7 has
> dropped i686 completely it seems.

This is XFS upstream response to the question I asked about i686 concerns, and they do test it and support it, although there is a limit to 16TB file systems (not an XFS limitation per se, as you'll read). But then such large file systems on 32-bit kernels is also not considered a good idea anyway even if it were ext4 (which by the way has the same 16TB limit.)

http://oss.sgi.com/archives/xfs/2014-02/msg00927.html

ARM is valid, but the ARM folks say their installation is typically kickstart. But I even if that's their primary install method  (?) I wouldn't want the secondary GUI method to blow up on them just because of the default file system. So yes we kinda need to know through some testing.


Chris Murphy