{"id":1426,"date":"2016-10-03T08:39:05","date_gmt":"2016-10-02T23:39:05","guid":{"rendered":"http:\/\/matoken.org\/blog\/?p=1426"},"modified":"2016-10-03T08:39:05","modified_gmt":"2016-10-02T23:39:05","slug":"without-knowing-that-swap-file-is-not-able-to-make-in-the-btrfs%ef%bf%bc%ef%bf%bc","status":"publish","type":"post","link":"https:\/\/matoken.org\/blog\/2016\/10\/03\/without-knowing-that-swap-file-is-not-able-to-make-in-the-btrfs%ef%bf%bc%ef%bf%bc\/","title":{"rendered":"Btrfs\u3067swap file\u304c\u4f5c\u308c\u306a\u3044\u3053\u3068\u3092\u77e5\u3089\u305a\u306b\u5d4c\u307e\u308b"},"content":{"rendered":"<p>\u30d5\u30a1\u30a4\u30eb\u304b\u3089swap\u3092\u8a2d\u5b9a\u3057\u3088\u3046\u3068\u3057\u3066\u5931\u6557\u3057\u307e\u3057\u305f\uff0e<\/p>\n<pre><code>$ fallocate -l 500M test\r\n$ \/sbin\/mkswap test\r\nmkswap: test: insecure permissions 0644, 0600 suggested.\r\nSetting up swapspace version 1, size = 500 MiB (524283904 bytes)\r\nno label, UUID=aaf26c11-4653-40d5-b279-faa7d8c8625d\r\n$ sudo chmod 600 test\r\n$ sudo chown 0.0 test\r\n$ ls -l test\r\n-rw------- 1 root root 524288000 10\u6708  3 07:26 test\r\n$ sudo swapon test\r\nswapon: \/home\/mk\/test: swapon failed: \u7121\u52b9\u306a\u5f15\u6570\u3067\u3059\r\n$ sudo swapon -v \/home\/mk\/test\r\nswapon: \/home\/mk\/test: found signature [pagesize=4096, signature=swap]\r\nswapon: \/home\/mk\/test: pagesize=4096, swapsize=524288000, devsize=524288000\r\nswapon \/home\/mk\/test\r\nswapon: \/home\/mk\/test: swapon failed: \u7121\u52b9\u306a\u5f15\u6570\u3067\u3059\r\n$ LANG=C sudo swapon -v \/home\/mk\/test\r\nswapon: \/home\/mk\/test: found signature [pagesize=4096, signature=swap]\r\nswapon: \/home\/mk\/test: pagesize=4096, swapsize=524288000, devsize=524288000\r\nswapon \/home\/mk\/test\r\nswapon: \/home\/mk\/test: swapon failed: Invalid argument<\/code><\/pre>\n<p>\u691c\u7d22\u3059\u308b\u3068Btrfs\u3067swap file\u304c\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u3066\u3044\u306a\u3044\u3068\u304b\uff0e\u77e5\u3089\u306a\u304b\u3063\u305forz<\/p>\n<ul>\n<li><a href=\"https:\/\/btrfs.wiki.kernel.org\/index.php\/FAQ#Does_btrfs_support_swap_files.3F\" title=\"Does btrfs support swap files?\">Does btrfs support swap files?<\/a><\/li>\n<\/ul>\n<p>\u6027\u80fd\u4f4e\u4e0b\u3059\u308b\u3051\u3069loop device\u3092\u4f7f\u3048\u3070\u3044\u3051\u308b\u3088\u3068\u3044\u3046\u30ef\u30fc\u30af\u30a2\u30e9\u30a6\u30f3\u30c9\u304c\uff0e<\/p>\n<p><em>A workaround, albeit with poor performance, is to mount a swap file via a loop device.<\/em><\/p>\n<p>\u8a66\u3057\u3066\u307f\u307e\u3059\uff0e<\/p>\n<pre><code>$ \/sbin\/losetup -l\r\n$ sudo \/sbin\/losetup loop0 .\/test\r\n$ \/sbin\/losetup -l\r\nNAME SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE DIO\r\n\/dev\/loop0 0 0 0 0 \/home\/mk\/test 0\r\n$ sudo swapon -v \/dev\/loop0\r\nswapon: \/dev\/loop0: found signature [pagesize=4096, signature=swap]\r\nswapon: \/dev\/loop0: pagesize=4096, swapsize=536870912, devsize=536870912\r\nswapon \/dev\/loop0\r\n$ \/sbin\/swapon -s\r\nFilename Type Size Used Priority\r\n\/dev\/dm-2 partition 16658428 0 -1\r\n\/dev\/loop0 partition 524284 0 -2<\/code><\/pre>\n<p>\u3046\u307e\u304f\u884c\u304d\u307e\u3057\u305f\uff0e \u3082\u3068\u306b\u623b\u3057\u3066\u304a\u304d\u307e\u3059\uff0e<\/p>\n<pre><code>$ sudo swapoff \/dev\/loop0\r\n$ sudo \/sbin\/losetup -d \/dev\/loop0\r\n$ sudo rm .\/test<\/code><\/pre>\n<p><iframe style=\"width:120px;height:240px;\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" frameborder=\"0\" src=\"\/\/rcm-fe.amazon-adsystem.com\/e\/cm?lt1=_blank&#038;bc1=000000&#038;IS2=1&#038;bg1=FFFFFF&#038;fc1=000000&#038;lc1=0000FF&#038;t=matokensmeme-22&#038;o=9&#038;p=8&#038;l=as4&#038;m=amazon&#038;f=ifr&#038;ref=as_ss_li_til&#038;asins=B01LW0241D&#038;linkId=0e7c17fb538b3e4ffbc8586167a1c09a\"><\/iframe><iframe style=\"width:120px;height:240px;\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" frameborder=\"0\" src=\"\/\/rcm-fe.amazon-adsystem.com\/e\/cm?lt1=_blank&#038;bc1=000000&#038;IS2=1&#038;bg1=FFFFFF&#038;fc1=000000&#038;lc1=0000FF&#038;t=matokensmeme-22&#038;o=9&#038;p=8&#038;l=as4&#038;m=amazon&#038;f=ifr&#038;ref=as_ss_li_til&#038;asins=B00TQMFOCW&#038;linkId=2cdd19895e6023edfba5c2f8c0e04f4e\"><\/iframe><iframe style=\"width:120px;height:240px;\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" frameborder=\"0\" src=\"\/\/rcm-fe.amazon-adsystem.com\/e\/cm?lt1=_blank&#038;bc1=000000&#038;IS2=1&#038;bg1=FFFFFF&#038;fc1=000000&#038;lc1=0000FF&#038;t=matokensmeme-22&#038;o=9&#038;p=8&#038;l=as4&#038;m=amazon&#038;f=ifr&#038;ref=as_ss_li_til&#038;asins=B01LYN4ODS&#038;linkId=e821d41719aff8227ee48758ffa3dd30\"><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u30d5\u30a1\u30a4\u30eb\u304b\u3089swap\u3092\u8a2d\u5b9a\u3057\u3088\u3046\u3068\u3057\u3066\u5931\u6557\u3057\u307e\u3057\u305f\uff0e $ fallocate -l 500M test $ \/sbin\/mkswap test mkswap: test: insecure permissions 064 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"webmentions_disabled_pings":false,"webmentions_disabled":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":4,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":""},"categories":[6],"tags":[163,162],"class_list":["post-1426","post","type-post","status-publish","format-standard","hentry","category-linux","tag-btrfs","tag-swap"],"_links":{"self":[{"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/posts\/1426","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/comments?post=1426"}],"version-history":[{"count":0,"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/posts\/1426\/revisions"}],"wp:attachment":[{"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/media?parent=1426"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/categories?post=1426"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/matoken.org\/blog\/wp-json\/wp\/v2\/tags?post=1426"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}