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Date:      Sun, 6 Sep 2015 18:18:32 -0400 (EDT)
From:      Rick Macklem <rmacklem@uoguelph.ca>
To:        Jordan Hubbard <jordanhubbard@icloud.com>
Cc:        freebsd-fs@freebsd.org, Rakshith Venkatesh <vrock28@gmail.com>
Subject:   Re: CEPH + FreeBSD
Message-ID:  <838814506.1858817.1441577912291.JavaMail.zimbra@uoguelph.ca>
In-Reply-To: <1564D4FA-9BE1-4E37-8E91-F14A009D6B62@icloud.com>
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Jordan Hubbard wrote:
>=20
> > On Sep 3, 2015, at 4:17 AM, Rick Macklem <rmacklem@uoguelph.ca> wrote:
> >=20
> > Slightly off topic but, btw, there is a port of GLusterFS and those fol=
ks
> > do seem
> > interested in seeing it brought "up to speed". I am not sure how mature=
 it
> > is at
> > this point, but it has been known to build on amd64. (I don't have an a=
md64
> > machine,
> > so I haven't gotten around to building/testing it, but I do plan to try=
 and
> > use
> > it as a basis for a pNFS server, if I can figure out how to get the FH =
info
> > out of it.
> > I'm working on that;-)
>=20
> There are at least two distributed (multi-node) object stores for FreeBSD
> that I know of.
>=20
> One is glusterfs, for which I=E2=80=99m not even really clear on the stat=
us of the
> ports for.  I don=E2=80=99t see any glusterfs port in the master branch o=
f
> https://github.com/freebsd/freebsd-ports (or
> https://github.com/freebsd/freebsd-ports/tree/branches/2015Q3 for that
> matter).
>=20
> Our FreeNAS ports tree (https://github.com/freenas/ports), in which we ha=
ve a
> bit more latitude to add and curate our own ports, has both a net/gluster=
fs
> and sysutils/glusterfs, from separate sources (looks like we need to clea=
n
> things up) - net/glusterfs lists craig001@lerwick.hopto.org as the
> MAINTAINER and is at version 3.6.2.  The sysutils/glusterfs port lists
> bapt@FreeBSD.org as the MAINTAINER and is at version 20140811.
>=20
> I=E2=80=99m not really sure about the provenance since we were simply eva=
luating
> glusterfs for awhile and may have pulled in interim versions from those
> sources, but obviously it would be best to have an official maintainer an=
d
> someone in the FreeBSD project actually curating a glusterfs port so that
> all users of FreeBSD can use it.  It would also be fairly key to your own
> efforts, assuming you decide to pursue glusterfs as a foundation technolo=
gy
> for pNFS.
>=20
> The other object store, which is pretty mature and is currently leading t=
he
> pack (of two :) ) for inclusion into FreeNAS is RiakCS from Basho.  There=
 is
> a port currently in databases/riak but it=E2=80=99s pretty out of date at=
 version
> 1.4.12 (the current version is 2.0.1, with 2.0 being a major upgrade of
> RiakCS).
>=20
> We are very interested in investigating various ways of shimming RiakCS t=
o
> NFS, using RiakCS a back-end store.   Is that something you=E2=80=99d be =
amenable to
> discussing?   I=E2=80=99d be happy to send you an amd64 architecture mach=
ine to
> develop on. :)
>=20
Hmm. From a quick look at their web page (I looked once before as well), I =
don't
think RiakCS has what I need to do pNFS in a reasonable (for me) amount of =
effort.
Two things that glusterFS has that I am hoping to use (and I don't think Ri=
akCS has
either of these) are:
- A Fuse file system interface which allows the kernel nfsd to access the s=
tore as
  a file system, so that it can provide the metadata services (NFS without =
the reads/writes).
- A userland NFSv3 server in each node which will allow the node to act as =
a data server.

If I am wrong and RiakCS does support a VFS file system interface (via Fuse=
 or ???), then
please correct me. With that, it might be a reasonable alternative.
I'll admit I've spent a little time looking at the glusterFS sources and ha=
ven't yet
solved the problem of how to generate the file handles I need, but that sou=
nds trivial
compared with an entire Fuse and/or VFS file system interface, I think?

In general, using a cloud object store to implement a pNFS server is a *mis=
*use of
the technology, imho. I think it may be possible with glusterFS, since that=
 technology
seems to be based on a cluster file system, which is what a pNFS server can=
 also use.

I think there would be a lot of work involved in mapping a POSIX file syste=
m onto the
Riak database and then exporting that via NFS, etc. It might also be more p=
ractical to
do this via a userland NFS service than the kernel based one currently in F=
reeBSD.
(glusterFS is starting to use the NFS-ganesha server, but I believe it is p=
retty Linux specific,
 so I doubt it would be useful for Riak running on FreeBSD?)

rick

> - Jordan
>=20
>=20



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