[Lustre-discuss] On which OSS are the OST?

[Christopher J. Morrone]

Richard Lefebvre wrote:
> Hi,
> 
> I have been going through the operations manual, but I can't find the 
> answer of how to find on which OSS each OST are?

Yes, that seems like an oversight to me too.  I'd like to see lfs have a 
new command to make this lookup easier.

If you have access to the servers, you could run something like:

   pdsh -w host[1-128] "lctl dl |grep obdfilter"

But if you want to figure it out from just one place, say a client, 
thats pretty difficult to piece together from the various commands.

Attached is my "ostmapping" script that you can run on a lustre client. 
  It farms various places: lfs, lctl, /proc, and lists all oss nids 
showing the osts that are currently being exported to the client on 
which you run the command.  If the nid looks like an IP address, it even 
tries to lookup the hostname associated with the address.

If anyone has a better way to do this, let me know!

Run "ostmapping -h" to see the options.  You can also ask it to just 
show the oss and osts for one filesystem, or just the osts for one oss.

Here's a sample of the its output:

172.16.2.1 at tcp (tycho1-lnet0)
     lc1-OST0000_UUID      0     ACTIVE
     lc1-OST0008_UUID      8     ACTIVE
     lc1-OST0010_UUID      16    ACTIVE
172.16.2.2 at tcp (tycho2-lnet0)
     lc1-OST0001_UUID      1     ACTIVE
     lc1-OST0009_UUID      9     ACTIVE
     lc1-OST0011_UUID      17    ACTIVE
172.16.2.3 at tcp (tycho3-lnet0)
     lc1-OST0002_UUID      2     ACTIVE
     lc1-OST000a_UUID      10    ACTIVE
     lc1-OST0012_UUID      18    ACTIVE
172.16.2.4 at tcp (tycho4-lnet0)
     lc1-OST0003_UUID      3     ACTIVE
     lc1-OST000b_UUID      11    ACTIVE
     lc1-OST0013_UUID      19    ACTIVE
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