[dm-devel] [End-User Q] Production quality of Fedora Core 2 (new install) with LVM2+Snapshots?

Bryan J. Smith b.j.smith at ieee.org
Sat Jul 24 15:37:20 UTC 2004

[ End-User level question ]

- Completely New Install:  Best Fedora release for Snapshots?

I'm going to be installing a new system*.
The storage array* will handle all the RAID functionality.
So there are no "upgrade" issues involved.

I want to use LVM/LVM2 to do snapshots and that's all.  Both for doing
backups as well as multiple, simultaneous snapshots (if possible?) for
quick file recovery.  Ala NetApp WAFL-like if possible (my client is
used to NetApp filers, but doesn't have any money these days), although
I don't expect the same performance-level (and they know this).  Just
the snapshot feature in itself is all I want.

- Never going to resize, hardware storage array handles 100% of RAID

I'm _never_ going to move/resize stuff, _period_, nor do any software
RAID (the storage array* will handle that).  So the LVM2 will just be
for managing a bunch of static extents as well as rotating snapshots on
an off-peak-hour basis.

- Best filesystem for reliable snapshots?  Largely a NFS server.

I'm open to either Ext3 or XFS as a filesystem, whatever works best and
reliably. I'd hesitate to use ReiserFS because of past NFS issues I've
had with it (I know the issues have been worked out), but this is an NFS
server first and foremost.  I'd like to use EA/ACLs (which I've always
loved on XFS), but if that is known to conflict/strain LVM[2], then it's
not a big deal (I assume not because it is a filesystem-level

In the end, I'm looking for the most stable Snapshot-filesystem
combination for serving largely NFS.  Other feature be damned if there
is an issue.

- Is Fedora Core 2 with kernel 2.6 and LVM2 best?  DM options?

I assume going with Fedora Core 2, Linux 2.6 and LVM2 is recommended?
Or are most trusting Linux 2.4 and older LVM for now?
I'd rather make this the least painful for upgrading in the future,
but if LVM2 snapshots are not trusted, at least compared to LVM, then I
will stick with FC1/LVM.

I was going through the FC2 kernels (e.g., latest 2.6.6) and there is no
FC2 kernel with dm yet.  I noted both the Red Hat 2.6.7 development
kernel release (which also includes the 3w-9xxx driver* which is nice)
as well as the change log for the stock kernel 2.6.8 development going
on now includes it.  I would rather avoid stock kernels

- Primary focus:  NFS (but not primary NFS server), then Samba

This is going to be a production NFS/Samba server.  BTW, it's not the
primary NFS server (and older NetApp is for that), but it does handle
the SMB traffic for non-engineering users, as well as handle
authentication and other details (e.g., serves out the automounter
maps).  EA/ACLs would be nice for Samba (I've likened to XFS for this
in the past), but not crucial.

- Best distro in 2 weeks:  FC2 + RH/DM kernel?  Other?

It will be loaded in around 2 weeks, given hardware procurement, server
rotation and other timing.  I'm looking for the best Fedora release at
that time.  I was hopeful that FC2 with a newer Red Hat kernel w/DM
would give me everything I need, and work reliably.  If sticking with
FC1 and LVM would be better, let me know.

I'd rather not go to FC3 Test since I assume it is still 2+ months away
from being a release candidate.  Unless, of course, the kernel-DM-user
space combination cannot be put onto FC2 reliably.  I'd have to 

Thank you very much in advance for your time and consideration.
I'm a published technical author (various CMP, MacMillan publications)
so if you need any documentation, let me know.

I'm also a closet C coder (coming from aerospace/semiconductor
industries), although I could probably only help with point patches of
things I'm testing.  But this is going to go into production, so I'd
rather avoid having to deal with that.  I've heard LVM2+DM is good, as
long as you don't do pvmoves with snapshots (don't plan on doing that,
since pvcreate is for snapshots, right?).

-- Bryan

*NOTE  It's actually a recycle of an old one with a new storage array
and _new_ Fedora install (previous fedora-list post):  

     Linux Enthusiasts call me anti-Linux.
   Windows Enthusisats call me anti-Microsoft.
 They both must be correct because I have over a
decade of experience with both in mission critical
environments, resulting in a bigotry dedicated to
 mitigating risk and focusing on technologies ...
           not products or vendors
Bryan J. Smith, E.I.            b.j.smith at ieee.org

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