[Lustre-discuss] Random OST Numbers chosen in a stripe

[Roger Spellman]

Suppose that I stripe a directory with the following command:

lfs setstripe  -c 4 .

On some of my systems, when I create file in the directory, the list of OSTs for a particular file is sequential, e.g.

   obdidx           objid          objid            group
    12               2            0x2                0
    13               2            0x2                0
    14               2            0x2                0
    15               2            0x2                0

On another one of my systems, when I create files in a similarly striped directory, I get seemingly random assignment, e.g.

For one file:

   obdidx           objid          objid            group
    14            6884         0x1ae4                0
    46            6880         0x1ae0                0
     8            6883         0x1ae3                0
    29            6880         0x1ae0                0

For a different file:

   obdidx           objid          objid            group
     13            6884         0x1ae4                0
     28            6880         0x1ae0                0
     44            6880         0x1ae0                0
     27            6880         0x1ae0                0

Why is this?  

How can I control it to always be sequential?

Thanks.

Roger Spellman
Staff Engineer
Terascala, Inc.
508-588-1501
www.terascala.com <http://www.terascala.com/>