UFS2 with 4TB disk _totally absurd_

Scott Long scottl at samsco.org
Sat Apr 8 14:46:58 UTC 2006


Ensel Sharon wrote:
> On Thu, 6 Apr 2006, Scott Long wrote:
> 
> 
>>Ensel Sharon wrote:
>>
>>>>The FDISK and bsdlabel schemes simply cannot deal with >2TB.  You'll
>>>>need to either put your filesystem directly on the storage device
>>>>without and slices/labels, or use GPT to create logical partitions.
>>>
>>>
>>>2TB filesystems are _not large_.  FreeBSD should expect 2-4TB
> 
> filesystems
> 
>>>to be in common use in peoples _living rooms_, never mind in the
> 
> office or
> 
>>>datacenter.
>>>
>>>So 5.x was a total wash in terms of UFS2 and snapshots, largefiles,
> 
> etc.,
> 
>>>6.0 still doesn't have working filesystem quotas or snapshots, and it
>>>seems, doesn't support modern (circa 2004) hard drives.
>>>
>>>Maybe a little less time working on FreeBSD 23.0 ... ?
>>>
>>
>>What are you talking about?  UFS2, the filesystem, supports storage
>>volumes up to 2^63 blocks in size, and filesystems themselves of
>>more than 2^53 blocks in size.  There is no 2TB limit in UFS2, and I've
>>personally created filesystems that are indeed much larger than that..
>>These sizes were supported in 2004, and they are supported in 2006.
>>What is limited is the FDISK and BSDLABEL formats, which were designed
>>in the early 80's to handle up to 2^32 blocks.  Neither of these prevent
>>you from creating a large filesystem.  Maybe you're looking to have a
>>single large volume to hold both your boot filesystem and your data
>>filesystem?  That's generally a bad idea since it puts more things into
>>the path of a failure.  Try doing what most people do, which is to boot
>>off of a 2 disk mirror (go big and get 500GB disks if you want) and have
>>your data on a separate array that is more redundant and doesn't need to
>>use the above partition formats.
>>
>>Alternatively, find a PC that understands how to boot off of GPT
>>partitions, and use that format.  It's not FreeBSD's fault that the PC
>>BIOS uses the FDISK format.  Go complain to IBM and Microsoft for not
>>having the foresight to future-proof their partition format 25 years
>>ago.
> 
> 
> 
> I'm not saying that you can't create 2+ TB filesystems.  I am saying that
> there are all sorts of problems with them, from snapshotting them, to
> fsck, to easy creation with sysinstall.
> 

You also can't configure WiFi with sysinstall.  Does that mean that WiFi
is broken in FreeBSD?  No, it means that sysinstall has outlived its 
usefulness by 5 years.

> And all the while, the reaction has been a non-chalant dismissiveness,
> presumably based on the fact that 2+ TB filesystems are out of the norm,
> or are "frontier" hardware or whatever.  I am writing to inform you that
> that is not the case, and has not been for quite some time.  I know many
> people with 2+ TB filesystems in their houses - I have one _attached to my
> television_.
> 
> So whereas the fact that fsck and snapshots and dump and restore and df
> and quotas are all broken on 2+ TB:
> 
> http://www.freebsd.org/projects/bigdisk/index.html
> 
> The thought was that that would get cleaned up circa 5.2 or
> something.  Here we are at 6.1 and it's still broken.  Perhaps when
> commodity disks exceed 50% of the size of the max known-working FreeBSD
> partition the urgency will increase ?
> 

You seem to know exactly what does and doesn't work, and you seem to
have a clue on how to make things work.  What we need is _help_ in these
areas, not people complaining about the obvious.  Are you willing to
help?

Scott


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