{"id":623,"date":"2018-06-13T11:09:02","date_gmt":"2018-06-13T16:09:02","guid":{"rendered":"http:\/\/csic.som.emory.edu\/~lzhou\/blogs\/?p=623"},"modified":"2018-06-13T11:09:02","modified_gmt":"2018-06-13T16:09:02","slug":"breaking-nfs-16-group-membership-limit","status":"publish","type":"post","link":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/?p=623","title":{"rendered":"Breaking NFS’ 16 group membership limit"},"content":{"rendered":"

The 16 group limit with auth_sys is not tuneable. It is defined in RFC_5331 and cannot be adjusted or patched.<\/p>\n

However for linux running nfs-utils version over 1.0.12 and kernel version over 2.6.21, you can make rpc.mountd to manage gid to avoid this limitation.<\/p>\n

To do this:<\/p>\n

    \n
  1. On all your nfs server, edit \/etc\/nfs.conf, add two lines:
    \n[mountd]
    \nmanage-gids=y
    \nTo be noted that the hint in nfs.conf is WRONG, which uses manage_gids instead of manage-gids.
    \nSave nfs.conf.<\/li>\n
  2. Restart your nfs daemon by running
    \nsystemctl restart nfs<\/li>\n
  3. Reload your shares by running
    \nexportfs -r<\/li>\n
  4. On your clients, run
    \nmount -o remount <your_shares><\/li>\n
  5. Log out and re-login your user, now the user is no longer limited by the 16 group membership limit.<\/li>\n
  6. To verify, log in your NFS server, run
    \ndate +%s &gt \/proc\/net\/rpc\/auth.unix.gid\/flush
    \ncat \/proc\/net\/rpc\/auth.unix.gid\/content
    \nYou will see things like
    \n#uid cnt: gids…
    \n0 9: 0 4 20 24 46 100 112 121 127
    \nThis means that the rpc.mountd is now managing the GIDs.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    The 16 group limit with auth_sys is not tuneable. It is defined in RFC_5331 and cannot be adjusted or patched. However for linux running nfs-utils version over 1.0.12 and kernel version over 2.6.21, you can make rpc.mountd to manage gid to avoid this limitation. To do this: On all your nfs server, edit \/etc\/nfs.conf, add […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,3],"tags":[],"class_list":["post-623","post","type-post","status-publish","format-standard","hentry","category-computer-tips","category-mri-technical-support","post-blog"],"_links":{"self":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts\/623","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=623"}],"version-history":[{"count":1,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts\/623\/revisions"}],"predecessor-version":[{"id":624,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=\/wp\/v2\/posts\/623\/revisions\/624"}],"wp:attachment":[{"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=623"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=623"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/csic.som.emory.edu\/~lzhou\/blogs\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=623"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}