[nycbug-talk] misc. meeting note (ike jail)

Jonathan jonathan
Fri Dec 9 06:00:29 EST 2005

Charles Sprickman wrote:
> All,
> I remember there being some question (not any idea anymore how it 
> related to jails) about large filesystems.  Ike answered that the 
> support for 2TB+ stank.  That sounded odd to me after hearing about UFS2 
> supporting much larger filesystems...
> This little article explains some of the issues:
> http://www.mostlygeek.com/node/39
> My favorite part is that disklabel can't deal with a partition larger 
> than 2TB.
> This references 5.4, any changes in 6.0?


Many systems don't require an MBR or GPT, and even PCs don't require it 
if booting and inter-operating with other OS's is not required. The next 
limit that comes in, though, is with the BSD disklabel. This label 
defines up to 8 partitions on a disk, MBR slice, or other storage extent 
for filesystems and swap space. Unfortunately, the on-disk format of the 
disk label again uses 32 bit quantities, so it is also limited to 2TB. 
Fixing this would require creating a new format that is incompatible 
with the old and would require an update to the FreeBSD boot loader. 
This would complicate interoperability and the upgrade path. Also, if a 
new format is going to be created, it should also address the 8 
partition limit that exists now. Given these requirements, it's tempting 
to just adopt the GPT format instead for secondary storage partitioning.


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