{"id":29384,"date":"2020-06-30T17:12:51","date_gmt":"2020-06-30T21:12:51","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=29384"},"modified":"2020-09-30T16:22:23","modified_gmt":"2020-09-30T20:22:23","slug":"apfs-and-time-machine-in-big-sur","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2020\/06\/30\/apfs-and-time-machine-in-big-sur\/","title":{"rendered":"APFS and Time Machine in Big Sur"},"content":{"rendered":"<p><a href=\"https:\/\/eclecticlight.co\/2020\/06\/29\/apfs-changes-in-big-sur-how-time-machine-backs-up-to-apfs-and-more\/\">Howard Oakley<\/a>:<\/p>\n<blockquote cite=\"https:\/\/eclecticlight.co\/2020\/06\/29\/apfs-changes-in-big-sur-how-time-machine-backs-up-to-apfs-and-more\/\"><p>APFS in macOS 11 changes volume roles substantially. The System volume within a boot Volume Group is now sealed using a tree of cryptographic hashes, as I have <a href=\"https:\/\/eclecticlight.co\/2020\/06\/25\/big-surs-signed-system-volume-added-security-protection\/\">detailed here<\/a>.<\/p><p>[&#8230;]<\/p><p>As 9to5Mac has <a href=\"https:\/\/9to5mac.com\/2020\/06\/26\/apple-apfs-encrypted-drive-support-apfs-time-machine-backups\/\">already reported<\/a>, Big Sur is the first version of macOS which can make Time Machine backups to APFS volumes without using a virtual HFS+ file system on a sparse bundle. However, to do so requires the destination APFS volume to be assigned the role of Backup, and allocation of storage space as a Physical Store.<\/p><p>[&#8230;]<\/p><p>APFS doesn&rsquo;t support directory hard links, so can&rsquo;t use the same mechanism when storing Time Machine backups. Instead, what appears to function as a form of virtual file system is created using new features in APFS. The volume assigned the role of Backup appears to be a regular APFS volume, and is protected from normal access, even by root. File data is kept as usual in the container&rsquo;s Physical Store, to which file data is copied during each backup. [&#8230;] This is synthesised into what is presented by the Finder as the customary hierarchy of files and folders, just as with HFS+ backups. However, matching unchanged folders have different <em>volume<\/em> numbers, as if they were stored on separate mounted volumes.<\/p><\/blockquote>\n<p>The updated APFS reference is <a href=\"https:\/\/developer.apple.com\/support\/downloads\/Apple-File-System-Reference.pdf\">here<\/a>. I plan to keep my Time Machine backups using HFS+ because of APFS&rsquo;s slow performance with spinning disks. Also, it&rsquo;s not clear to me whether this synthesized display will cause problems accessing the backed up files using other apps or cloning the backup drive.<\/p>\n\n<p>Previously:<\/p>\n<ul>\n<li><a href=\"https:\/\/mjtsai.com\/blog\/2020\/06\/23\/macos-11-0-big-sur-announced\/\">macOS 11.0 Big Sur Announced<\/a><\/li>\n<li><a href=\"https:\/\/mjtsai.com\/blog\/2019\/09\/19\/apfs-enumeration-performance-on-rotational-hard-drives\/\">APFS Enumeration Performance on Rotational Hard Drives<\/a><\/li>\n<\/ul>\n\n<p id=\"apfs-and-time-machine-in-big-sur-update-2020-09-30\">Update (2020-09-30): See also: <a href=\"https:\/\/news.ycombinator.com\/item?id=24621300\">Hacker News<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"<p>Howard Oakley: APFS in macOS 11 changes volume roles substantially. The System volume within a boot Volume Group is now sealed using a tree of cryptographic hashes, as I have detailed here.[&#8230;]As 9to5Mac has already reported, Big Sur is the first version of macOS which can make Time Machine backups to APFS volumes without using [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"2020-06-30T21:12:56Z","apple_news_api_id":"00bc7fc7-dbc0-4976-bdca-83dd800d282a","apple_news_api_modified_at":"2020-09-30T20:22:26Z","apple_news_api_revision":"AAAAAAAAAAAAAAAAAAAAAA==","apple_news_api_share_url":"https:\/\/apple.news\/AALx_x9vASXa9yoPdgA0oKg","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[2],"tags":[1395,146,30,1891,216],"class_list":["post-29384","post","type-post","status-publish","format-standard","hentry","category-technology","tag-apple-file-system-apfs","tag-backup","tag-mac","tag-macos-11-0","tag-timemachine"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/29384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=29384"}],"version-history":[{"count":2,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/29384\/revisions"}],"predecessor-version":[{"id":30296,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/29384\/revisions\/30296"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=29384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=29384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=29384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}