{"id":349,"date":"2010-02-18T02:54:22","date_gmt":"2010-02-18T07:54:22","guid":{"rendered":"http:\/\/yourlinuxguy.com\/?p=349"},"modified":"2010-02-18T06:36:31","modified_gmt":"2010-02-18T11:36:31","slug":"why-cant-i-unmount-my-mount","status":"publish","type":"post","link":"https:\/\/yourLinuxGuy.com\/?p=349","title":{"rendered":"Why can’t I unmount my mount?"},"content":{"rendered":"

This basic (re-worded) question came in from Jeff: “Why won’t my remote filesystem mount unmount when I try the umount<\/code> command?<\/em>”<\/p>\n

It’s very true:\u00a0 If you try to umount<\/code> (unmount) a filesystem that is currently being accessed, it will not let you do it.\u00a0 And it will tell you something like, “umount: \/media\/ncp: device is busy<\/code>“.\u00a0 What causes this?\u00a0 Well, it’s likely to be one of two things:<\/p>\n

    \n
  1. You have (or someone else has) cd<\/code>‘d onto the remote filesystem and are currently at or below the mount point root<\/li>\n
  2. You are running an application that has a file open on that mount point<\/li>\n<\/ol>\n

    To mitigate item #1 above (if you are the guilty party, not someone else), just cd<\/code> to the filesystem root (like cd \/<\/code>), or some other place you know is not on the mount point (like cd \/tmp<\/code>).\u00a0 Then you can run your umount<\/code> command.<\/p>\n

    Solving item #2 above is perhaps a tad more tricky.\u00a0 Of course, if you have a suspicion or direct knowledge of the guilty app, then you can just stop it.\u00a0 Sometimes doing this:<\/p>\n

    ps -ef | grep <\/code>
    \n…or…
    \nps aux |grep <\/code><\/p>\n

    …will show the process and any files it accessed by the startup command.<\/p>\n

    Either way, my favorite way to check for both item #1 and #2 above is to use lsof<\/code>.\u00a0 This utility will list *every* file that the system has a hold on.\u00a0 And this is essential because after all, we know that Linux is nothing but a bunch of files, right?<\/p>\n

    So here’s what I like to do, for example:<\/p>\n

    lsof| grep \"\/media\"<\/code><\/p>\n

    … this will show you if anyone or anything is currently sitting on the mountpoint (of course, change your mountpoint to suit, be it \/media<\/code>, \/mnt<\/code>, \/export<\/code>, whatever).\u00a0 If it shows anything, you can see who or what is at fault, and tell them to get off it, or kill them (I mean the app, jeez…).\u00a0 If you really need to see the headers of the columns, you can do a double-run for cosmetic purposes that will run once for just the header, then again to grab your detail, like this:<\/p>\n

    lsof |head -1;lsof| grep \"\/media\"<\/code><\/p>\n

    Another way is to use the fuser<\/code> command, referencing your mount point. Here’s my favorite set of flags in an example:<\/p>\n

    fuser -uv \/media\/ncp<\/code><\/p>\n

    I hope that helps!<\/p>\n

    8)<\/p>\n","protected":false},"excerpt":{"rendered":"

    This basic (re-worded) question came in from Jeff: “Why won’t my remote filesystem mount unmount when I try the umount command?” It’s very true:\u00a0 If you try to umount (unmount) a filesystem that is currently being accessed, it will not…
    Read more<\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[11,47,81],"tags":[],"class_list":["post-349","post","type-post","status-publish","format-standard","hentry","category-intermediate","category-linuxgeneral","category-lsof"],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pnjn1-5D","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=\/wp\/v2\/posts\/349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=349"}],"version-history":[{"count":15,"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=\/wp\/v2\/posts\/349\/revisions"}],"predecessor-version":[{"id":351,"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=\/wp\/v2\/posts\/349\/revisions\/351"}],"wp:attachment":[{"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yourLinuxGuy.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}