Lustre discuss - Jan 2008 - getting filesystem metadata

whats the most efficient way to get data from lustre about files?

We need to automate getting information like atime mtime size and  
owner out of the filesystem.

It appears if i do a find that the OST''s still do allot of disk  
seeks.  Is there a way to explicitly pull this data from just the mdt  
with out walking all 3 TB of data?


Brock Palen
Center for Advanced Computing
brockp at umich.edu
(734)936-1985

On 21 Jan 2008, at 15:03, Brock Palen wrote:
> It appears if i do a find that the OST''s still do allot of disk
> seeks.  Is there a way to explicitly pull this data from just the mdt
> with out walking all 3 TB of data?
I don''t think there''s a "nice" way to do this just
yet.

We snapshot the MDS volume, mount the snapshot, and then trawl  
through that. It''s an order of magnitude faster than walking the  
lustre filesystem for what we are doing (building file lists for  
incremental backups). You can''t get size information off the MDS  
(yet) though.

Depending on exactly what you need to do, you might be able to use  
e2scan (check bug #13108 for details)