gmirror disks vs partitions

[Tom Samplonius]

----- Vulpes Velox <v.velox at vvelox.net> wrote:
> On Thu, 18 Jan 2007 10:15:56 +0900
> "Adrian Chadd" <adrian at freebsd.org> wrote:
> 
> > On 17/01/07, Andrew Pantyukhin <infofarmer at freebsd.org> wrote:
> > 
> > > [...after reading the slashdotter's piece of wisdom...]
> > >
> > > Yes, but that's the kind of functionality I have always
> > > expected to be present in software raid solutions. I
> > > hope I'll live to see this implemented in geom.
> > 
> > That made my eyes bleed.
> > 
> > Bring on ZFS and its method of managing JBODs.
> 
> I second that. I have been way less than impressed with software raid
> and LVM on linux.
...

  But LVM by itself is a good volume manager.  The block level snapshot ability is especially good.  LVM can actually notify dependent filesystems so that they flush all data, when the block level snapshot is created.  ext3 does not support filesystem based snapshots (like ufs2 does), but LVM snapshots are better than most filesystem snapshots.

  ZFS is clearly better than LVM+ext3, and is really the only option for really big filesystems right now.  ufs2 doesn't support journaling, and background fsck isn't a complete replacement for journalling.  ext3 is stable but doesn't really scale well, or have leading performance, and doesn't really work on FreeBSD anyways.  XFS is virtually unsupported, as SGI laid off all their filesystem developers when they went into chapter 11, and ReiserFS, besides having some dodgy reliability issues, the head of development is currently in jail for suspicion of murder.  So besides, being the best, ZFS is nearly the only choice for really big filesystems.

Tom