Re: [tlug] Help with fsck and ocfs2 (or even ext4?)...

[Christian Horn <chorn@example.com>]

On Mon, Sep 20, 2021 at 12:12:21AM +0200, Christian Horn wrote:
> > I asked on ServerFault and a couple of people clarified to me that ext4
> > wouldn't work.  I still don't understand it...I thought a SAN could look
> > after the disk the same way a server looks after an ext4 disk that is NFS
> > exported...

I might as well comment on alternative setups:

a) NFS server
   + you access the 70TB with one system, run ext4 or XFS
   + you have no cluster infrastructure, easy to maintain
   - if that NFS service is down, your clients can not access
     the data.  But in that case, you could just manually
     make one of the other systems the NFS server (if they
     still all have access to the block device)

b) NFS server, clustered: 2 systems, cluster like pacemaker,
   virtual IP, ext4/XFS on the 70TB, if one server goes down
   the other mounts the 70TB and offers the service
   + you still just need the 70TB storage
   - but a second system, and need to administer a cluster

c) Ceph: all of the systems have a bit local storage, i.e.
   20TB.  The systems then "work" together with ceph, and
   together present a 70TB volume.  Your systems/storage 
   should be enough so you have all data twice, so one
   system can go down without the 70TB data becoming un-
   available.
   - needs kind of "coordinating" infra again, ceph here
   - and each system accessing a bit of storage, instead
     of one big chunk

Chris