[Ocfs2-users] 16TB limitation

[Joel Becker]

On Thu, Feb 26, 2009 at 12:21:54PM -0800, Adam Schrotenboer wrote:
> Is the 16TB limitation per-node, or for the aggregate filesystem?
> 
> Also, is the 16TB limit only in 1.2, or also in 1.4?

	The limit is for the entire filesystem, but it doesn't come from
ocfs2 itself.  ocfs2 can address 16TB with 4K clusters up to 4PB with 1M
clusters.  The limitation comes from the Linux Journaled Block Device
(JBD).  This is what ocfs2 uses for its journaling in 1.2 and 1.4.
	Linux now has a new version of JBD, called JBD2.  This version
relaxes the limit, allowing ocfs2 to support larger volumes.  ocfs2 in
the mainline Linux kernel is already doing this.  However, JBD2 support
is not yet in 1.4.  We hope to provide that support later in the year.

Joel

-- 

Life's Little Instruction Book #450

	"Don't be afraid to say, 'I need help.'"

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127