[Lustre-discuss] Trying to mount lustre on a client when one or more OST is disabled

[Bob Ball]

I am trying to get a lustre client to mount the service, but with one or 
more OST disabled.  This does not appear to be working.  Lustre version 
is 1.8.4.

  mount -o localflock,exclude=umt3-OST0019 -t lustre 
10.10.1.140 at tcp0:/umt3 /lustre/umt3

dmesg on this client shows the following during the umount/mount sequence:

Lustre: client ffff810c25c03800 umount complete
Lustre: Skipped 1 previous similar message
Lustre: MGC10.10.1.140 at tcp: Reactivating import
Lustre: 450250:0:(obd_mount.c:1786:lustre_check_exclusion()) Excluding 
umt3-OST0019 (on exclusion list)
Lustre: 450250:0:(obd_mount.c:1786:lustre_check_exclusion()) Skipped 1 
previous similar message
Lustre: 5942:0:(client.c:1476:ptlrpc_expire_one_request()) @@@ Request 
x1354682302740498 sent from umt3-MDT0000-mdc-ffff810628209000 to NID 
10.10.1.49 at tcp 0s ago has failed due to network error (5s prior to 
deadline).
   req at ffff810620e66400 x1354682302740498/t0 
o38->umt3-MDT0000_UUID at 10.10.1.49@tcp:12/10 lens 368/584 e 0 to 1 dl 
1292342239 ref 1 fl Rpc:N/0/0 rc 0/0
Lustre: 5942:0:(client.c:1476:ptlrpc_expire_one_request()) Skipped 1 
previous similar message
Lustre: Client umt3-client has started

When I check following the mount, using "lctl dl", I see the following, 
and it is clear that the OST is active as far as this client is concerned.

  19 UP osc umt3-OST0018-osc-ffff810628209000 
05b29472-d125-c36e-c023-e0eb76aaf353 5
  20 UP osc umt3-OST0019-osc-ffff810628209000 
05b29472-d125-c36e-c023-e0eb76aaf353 5
  21 UP osc umt3-OST001a-osc-ffff810628209000 
05b29472-d125-c36e-c023-e0eb76aaf353 5

Two questions here.  The first, obviously, is what is wrong with this 
picture?  Why can't I exclude this OST from activity on this client?  Is 
it because the OSS serving that OST still has the OST active?  If the 
OST were deactivated or otherwise unavailable on the OSS, would the 
client mount then succeed to exclude this OST?  (OK, more than one 
question in the group....)

Second group, what is the correct syntax for excluding more that one 
OST?  Is it a comma-separated list of exclusions, or are separate 
excludes required?

  mount -o localflock,exclude=umt3-OST0019,umt3-OST0020 -t lustre 
10.10.1.140 at tcp0:/umt3/lustre/umt3
                or
  mount -o localflock,exclude=umt3-OST0019,exclude=umt3-OST0020 -t 
lustre 10.10.1.140 at tcp0:/umt3 /lustre/umt3

Thanks,
bob