[lustre-discuss] [EXTERNAL] Re: OST not being used

Mohr, Rick mohrrf at ornl.gov
Mon Jul 12 08:14:54 PDT 2021


Sorry this response is a bit late, but I thought I would add a bit of info in case you ever run across the problem again.

Since the mds assigns osts for new files, you may want to check if the mds can contact the oss server.  If the mds thinks those osts are unavailable, it won't assign them to new files (even if the client has no problem accessing those osts).   Also, is it possible that an admin marked those osts as inactive on the mds?  Sometimes that is done to prevent new data from going to certain osts (for instance, if they were getting very full), but the clients still see those osts as active which allows them the continue reading from existing files that already reside on those osts.

Just a couple of possibilities you might want to check if you run into this problem again.


On 6/23/21, 10:46 AM, "lustre-discuss on behalf of Alastair Basden" <lustre-discuss-bounces at lists.lustre.org on behalf of a.g.basden at durham.ac.uk> wrote:

    Hi Megan,

    Thanks - yes, lctl ping responds.

    In the end, we did a writeconf, and this seems to have fixed the problem, 
    so probably some previous transient.  I would however have expected it to 
    heal whilst online - taking the filesystem down and doing a writeconf 
    seems a bit drastic!


    On Wed, 23 Jun 2021, Ms. Megan Larko via lustre-discuss wrote:

    > Hi!
    > Does the NIC on the OSS that serves OST 4-7 respond to an lctl ping? 
    > You indicated that it does respond to regular ping, ssh, etc.  I would 
    > review my /etc/lnet.conf file for the behavior of a NIC that times out. 
    > Does the conf allow for asymmetrical routing?  (Is that what you wish?) 
    > Is there only one path to those OSTs or is there a way failover NIC 
    > address that did not work in this even for some reason?
    > The Lustre Operations Manual Section 9.1 on lnetctl command shows how you can get more info on the NIC ( lnetctl show...)
    > Good luck.
    > megan
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