[Lustre-discuss] Disappearing OSTs

[Bernd Schubert]

Hello Thomas,

On Monday 05 May 2008 18:53:12 Thomas Roth wrote:
> Hello Bernd,
>
> could you give some details on the data corruption you have seen?
> We have been using GPT tables for some time now, but the partitions have
> been filled up only on NFS servers, not on Lustre OSS. And on these NFS
> volumes there were no problems attributed to the partition size.

the type of filesystem is not important at all, it is still on low device 
level.

>
> This would also depend on the actual size limit: I understand GPT tables
> are necessary for partitions > 2TB. The largest partition I have set up
> so far was 3.2 TB, so if you are sure about your number of 4 TiB, we
> might simply be on the lucky side.

I'm rather sure we did see the problem with >4TiB only. 

>
> And the workaround is specifying "gpt" on the kernel command line ? For
> once an easy solution ;-)

Yes, usually the kernel seems to first try the dos partition table and then 
tries other tables. But the first 512B of GPT seems to be compatible with DOS 
and so the kernel thinks the dos-table is fine.
When you specify gpt, it first tries gpt and if this doesn't fit it switches 
to dos.


Cheers,
Bernd

-- 
Bernd Schubert
Q-Leap Networks GmbH