Yesterday I noticed that my Arq backup was taking longer than usual. I recently added ~/Library to the back up and apparently that folder also contains an iMazing cache folder, with 10+ GB ipsw image files…
~/Library folder?Yes. I backup my entire Library folder, with the standard Arq exclusions (see below).
Apple keeps changing things, hiding folders, moving files from one location to another, etc. So, from time to time, I create a fake backup plan and update my exclusion list with the changes Arq includes in their default list. Then I delete the fake plan.
Over the years I’ve added a few exclusions of my own, like *.eflibrary, but nothing in the Library.
.DocumentRevisions-V100
.MobileBackups
.MobileBackups.trash
.Spotlight-V100
.TemporaryItems
.Trash
.Trashes
.dbfseventsd
.dropbox
.dropbox.cache
.fseventsd
.hotfiles.btree
.vol
Backups.backupdb
Cache
Caches
DerivedData
node_modules
Logs
com.apple.milod
*/iTunes/iTunes Media/Downloads
*/iTunes/iTunes Media/Podcasts
*/iTunes/Album Artwork
*/iTunes/Previous iTunes Libraries
*/Library/Application Support/CrashReporter
*/Library/Application Support/Dropbox
*/Library/Application Support/Google
*/Library/Application Support/MobileSync/Backup
*/Library/Application Support/com.apple.LaunchServicesTemplateApp.dv
*/Library/Biome
*/Library/Caches
*/Library/Containers/com.apple.mail/Data/Library/Mail Downloads
*/Library/Containers/com.apple.mail/Data/DataVaults
*/Library/Developer
*/Library/Google/GoogleSoftwareUpdate
*/Library/Metadata/CoreSpotlight
*/Library/Mirrors
*/Library/PubSub/Database
*/Library/PubSub/Downloads
*/Library/PubSub/Feeds
*/Library/Safari/Favicon Cache
*/Library/Safari/Icons.db
*/Library/Safari/Touch Icons Cache
*/Library/Safari/WebpageIcons.db
*/Library/Safari/HistoryIndex.sk
*/Library/VoiceTrigger/SAT
*/MailData/AvailableFeeds
*/MailData/BackingStoreUpdateJournal
*/MailData/Envelope Index
*/MailData/Envelope Index-journal
*/MailData/Envelope Index-shm
*/MailData/Envelope Index-wal
/.DS_Store
/.VolumeIcon.icns
/.fseventsd
/.vol
/.file
/.nofollow
/.noresolve
/System
/bin
/cores
/dev
/etc
/home
/macOS Install Data
/mnt
/net
/private
/sbin
/tmp
/usr
/var
Thank you for sharing your elaborate list!
I have been using Arq for years and it never occurred to me to use such exclusion list…
(I have been manually including/excluding files all this time… 
)
I’m askng cause I’ve never found the need to do so or tools to make this useful.
Random example: the configuration of DOSBox is stored in that folder.
I have manully coped ~/Library from an old Mac to a new Mac just in case, but never found the need to use that and I imagine messing with the content of a “live” ~/Library folder could do more harm than good.
If I ever need to restore my Mac, I wouldn’t restore ~/Library as a whole, but it’s nice to have individual files in the backup if (I discover that) I need them.
I generally look at the number of files in a folder, and then determine whether or not to exclude it or not. “Better safe than sorry”.
I agree with the “I’ve never needed it” sentiment. But once you exclude the worst offenders (caches in particular) it’s usually not too onerous to back it up.
Files stored in iCloud, and then deleted (from any of your Apple devices connected to iCloud) , are not recoverable after 30 days.
So I backup my Library folder so I can recover those files when I discover they are missing. Regardless of when they were lost/deleted.
I also backup ~/Library, with the default extension exceptions in the standard Backblaze configuration. I don’t trust myself to understand what subfolders of the library matter and which don’t matter for any particular app. Too fiddly to do otherwise.
Katie
I don’t to be honest, the only risk that I face is if iMessages cloud sync goes to hell, i’ll have lost messages (but i really don’t think id care).
I backup my iCloud and OneDrive by other means as backing up from downloaded files in library folder isn’t a good idea at all.