[Lustre-discuss] questions about an OST content

[Bob Ball]

I am emptying a set of OST so that I can reformat the underlying RAID-6 
more efficiently.  Two questions:
1. Is there a quick way to tell if the OST is really empty?  lfs_find 
takes many hours to run.
2. When I reformat, I want it to retain the same ID so as to not make 
"holes" in the list.  From the following information, am I correct to 
assume that the id is 24?  If not, how do I determine the correct ID to 
use when we re-create the file system?

/dev/sdj              3.5T  3.1T  222G  94% /mnt/ost51
  10 UP obdfilter umt3-OST0018 umt3-OST0018_UUID 547
umt3-OST0018_UUID           3.4T        3.0T      221.1G  88% 
/lustre/umt3[OST:24]
  20 IN osc umt3-OST0018-osc umt3-mdtlov_UUID 5

Thanks much,
bob