I am having trouble deactivating the OSTs following the instructions on the page: http://wiki.lustre.org/manual/LustreManual18_HTML/ConfiguringLustre.html#50651184_pgfId-1298977 All our servers are RHEL 5.5 with the lustre version 1.8.6 running the kernel 2.6.18-238.12.1.el5_lustre.g266a955 . The lustre client version is still 1.8.5. I am trying to deactivate the following OSTs and executed the following command for each of the OST: lctl --device 66 deactivate 66 IN osc lqcdproj-OST003c-osc lqcdproj-mdtlov_UUID 5 67 IN osc lqcdproj-OST003d-osc lqcdproj-mdtlov_UUID 5 68 IN osc lqcdproj-OST003e-osc lqcdproj-mdtlov_UUID 5 69 IN osc lqcdproj-OST003f-osc lqcdproj-mdtlov_UUID 5 70 IN osc lqcdproj-OST0040-osc lqcdproj-mdtlov_UUID 5 71 IN osc lqcdproj-OST0041-osc lqcdproj-mdtlov_UUID 5 72 IN osc lqcdproj-OST0042-osc lqcdproj-mdtlov_UUID 5 73 IN osc lqcdproj-OST0043-osc lqcdproj-mdtlov_UUID 5 74 IN osc lqcdproj-OST0044-osc lqcdproj-mdtlov_UUID 5 75 IN osc lqcdproj-OST0045-osc lqcdproj-mdtlov_UUID 5 76 IN osc lqcdproj-OST0046-osc lqcdproj-mdtlov_UUID 5 77 IN osc lqcdproj-OST0047-osc lqcdproj-mdtlov_UUID 5 A few minutes after I execute this command I see the following evictions on the OSSs: - - - - - - - - - - - - - - dslustre11 - - - - - - - - - - - - - - Lustre: lqcdproj-OST003c: haven''t heard from client lqcdproj-mdtlov_UUID (at 172.19.11.211 at tcp) in 227 seconds. I think it''s dead, and I am evicting it. Lustre: Skipped 5 previous similar messages - - - - - - - - - - - - - - dslustre12 - - - - - - - - - - - - - - Lustre: lqcdproj-OST0044: haven''t heard from client lqcdproj-mdtlov_UUID (at 172.19.11.211 at tcp) in 227 seconds. I think it''s dead, and I am evicting it. Lustre: Skipped 5 previous similar messages Lustre: lqcdproj-OST0046: haven''t heard from client lqcdproj-mdtlov_UUID (at 172.19.11.211 at tcp) in 227 seconds. I think it''s dead, and I am evicting it. Lustre: Skipped 2 previous similar messages And they receive MDS connection once I re-activate those OSTs again by executing the following command for each OST: lctl --device 66 activate - - - - - - - - - - - - - - dslustre11 - - - - - - - - - - - - - - Lustre: lqcdproj-OST003c: received MDS connection from 172.19.11.211 at tcp Lustre: Skipped 2 previous similar messages Lustre: lqcdproj-OST003f: received MDS connection from 172.19.11.211 at tcp Lustre: Skipped 1 previous similar message - - - - - - - - - - - - - - dslustre12 - - - - - - - - - - - - - - Lustre: lqcdproj-OST0042: received MDS connection from 172.19.11.211 at tcp Lustre: lqcdproj-OST0047: received MDS connection from 172.19.11.211 at tcp Lustre: Skipped 4 previous similar messages The lustre clients eventually loose connection to the above OSTs and the "lfs check servers" reports the following error: error: check ''lqcdproj-OST003e-osc-ffff88021ee57800'' Resource temporarily unavailable I would really appreciate it if someone could point to the correct procedure to "Removing an OST from the File System". Does execution of "lfs check servers" after doing a "lctl conf_param <OST name>.osc.active=0" still crash the node or has that problem been fixed over the last few versions? Thanks in advance for your help. Nirmal