[Ocfs2-users] Maximum volume size for OCFS2?

[Sunil Mushran]

Please re-read the FAQ entry.

# Is there a limit to the size of an ocfs2 file system?
Yes, current software addresses block numbers with 32 bits. So the file 
system device is limited to (2 ^ 32) * blocksize (see mkfs -b). With a 
4KB block size this amounts to a 16TB file system. This block addressing 
limit will be relaxed in future software. At that point the limit 
becomes addressing clusters of 1MB each with 32 bits which leads to a 
4PB file system.

The addressing limit is in JBD, in that it can only address 4 billion 
blocks.
The fix for this I believe is in mainline so technically the mainline branch
should be able to go full 4PB... but safe to say that's never been tested.

The one shipped with SLES is limited to 16TB.

Patrick J. LoPresti wrote:
> I apologize for bothering the list, but the information I have found
> is contradictory.
>
> According to http://oss.oracle.com/projects/ocfs2/dist/documentation/ocfs2_faq.html#LIMITS
> , the maximum volume size is 16TB.
>
> According to http://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits
> , it's 4PB.
>
> According to http://ocw.novell.com/suse-linux-enterprise/migrating-from-redhat-to-suse-linux-enterprise-server-10/3068_10_manual.pdf
> , it's "4 TB / 16 TB / 4 PB", with no indication of which.
>
> I am using Suse Enterprise Linux 10 SP1 on x86_64.  For my
> application, a 16TB volume is not sufficient, but a 4PB volume would
> be.
>
> So:
>
>     Can I create a volume larger than 16TB?  If so, is there any
> special procedure I should know about?
>
> (Also, one or more of the references above should probably be updated.)
>
> Thank you!
>
>  - Pat
>
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