[lustre-discuss] Deactivate an OST for new file write operations

[Bob Ball]

We just built a new 2.7.0 Lustre file system.  Overall I'm happy with 
performance, but something is confusing me.

We have a combined mgs/mdt DataStore.  On that server I issue:
...
  20 UP osp umt3B-OST000b-osc-MDT0000 umt3B-MDT0000-mdtlov_UUID 5
[root at mdtmgs ~]# lctl --device 20 deactivate

/var/log/messages logs the change
2015-05-04T13:22:38-04:00 mdtmgs.aglt2.org kernel: [4051367.295627] 
Lustre: setting import umt3B-OST000b_UUID INACTIVE by administrator request

BUT, lctl dl still shows the device UP, not IN, as the manual, and past 
experience with older Lustre versions had led me to expect.  On the OSS, 
this logs:
2015-05-04T13:26:21-04:00 umdist09.aglt2.org kernel: [2694525.765701] 
Lustre: umt3B-OST000b: haven't heard from client 
umt3B-MDT0000-mdtlov_UUID (at 10.10.2.173 at tcp) in 227 seconds. I think 
it's dead, and I am evicting it. exp ffff88400a679800, cur 1430760381 
expire 1430760231 last 1430760154

lctl dl on that OSS now shows
  35 UP osd-zfs umt3B-OST000b-osd umt3B-OST000b-osd_UUID 5
  36 UP obdfilter umt3B-OST000b umt3B-OST000b_UUID 401
  37 UP lwp umt3B-MDT0000-lwp-OST000b umt3B-MDT0000-lwp-OST000b_UUID 5

The 401 count is 2 smaller than for the other OST on this server.

Note the time delay in the message logged on the OSS.  So, what is wrong 
with this picture?  Is this OST really de-activated for write 
operations?  And if it is, why does lctl still show it as UP and not as IN?

bob