filesystems bigger than 16 TB?

filesystems bigger than 16 TB?

[Tomasz Chmielewski]

With mkfs.ext4 from 1.41.14, it is not possible to create a filesystem 
which is bigger than 16 TB:


mkfs.ext4: Size of device /dev/sdb too big to be expressed in 32 bits
	using a blocksize of 4096.


But I see it succeeds with the latest git version of e2fsprogs.



The question is: how reliable such a filesystem is?

On a system which is supposed to be reliable, perhaps I'll be better off 
with xfs for such large filesystems?

I'm using Debian Squeeze, which has a 2.6.32 kernel.


-- 
Tomasz Chmielewski
http://wpkg.org

Re: filesystems bigger than 16 TB?

[Andreas Dilger]

On 2011-06-23, at 5:35 AM, Tomasz Chmielewski wrote:
> With mkfs.ext4 from 1.41.14, it is not possible to create a filesystem which is bigger than 16 TB:
> 
> mkfs.ext4: Size of device /dev/sdb too big to be expressed in 32 bits
> 	using a blocksize of 4096.
> 
> But I see it succeeds with the latest git version of e2fsprogs.
> 
> 
> 
> The question is: how reliable such a filesystem is?
> 
> On a system which is supposed to be reliable, perhaps I'll be better off with xfs for such large filesystems?
> 
> I'm using Debian Squeeze, which has a 2.6.32 kernel.

We are starting to use filesystems over 16TB, so far without problems.
Kernel is either RHEL5.4 (2.6.18), or RHEL6.1 (2.6.32), with e2fsprogs
from git (based on 7d9e31655fca48e9d6c2647ad443124113508b73).

We've tested up to 24TB quite a bit, and recently started testing a 128TB
filesystem and haven't run into any problems.  Beyond 128TB there are
some memory allocation issues that prevent the filesystem from mounting,
but aren't critical to be fixed quite yet...

Cheers, Andreas

Re: filesystems bigger than 16 TB?

[Dave Chinner]

On Thu, Jun 23, 2011 at 01:35:59PM +0200, Tomasz Chmielewski wrote:
> With mkfs.ext4 from 1.41.14, it is not possible to create a
> filesystem which is bigger than 16 TB:
> 
> 
> mkfs.ext4: Size of device /dev/sdb too big to be expressed in 32 bits
> 	using a blocksize of 4096.
> 
> 
> But I see it succeeds with the latest git version of e2fsprogs.
> 
> 
> 
> The question is: how reliable such a filesystem is?

Regardless of the filesystem or the feature, if it is not in
officially released packages, do you really want to risk your
production data on an experimental filesystem/feature?

> On a system which is supposed to be reliable, perhaps I'll be better
> off with xfs for such large filesystems?
> 
> I'm using Debian Squeeze, which has a 2.6.32 kernel.

On a 2.6.32 kernel, I'd strongly recommend using XFS for >16TB
filesystems....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com