This must be the reason that Time Machine has often told me that it found problems and I would have to start from scratch.
I, too, have never really liked Time Machine (too unreliable), but I never had a reason other than anecdotal experience. Bill > On May 7, 2018, at 11:41, Lee Larson <[email protected]> wrote: > > This whole thing about hard links got me curious and I did some Googling. > Here’s an excerpt from an old article on Ars Technica that states pretty > clearly what I think. > > >> One particularly scary example is the implementation of hard links on HFS+. >> To keep track of hard links, HFS+ creates a separate file for each hard link >> inside a hidden directory at the root level of the volume. Hidden >> directories are kind of creepy to begin with, but the real scare comes when >> you remember that Time Machine is implemented using hard links to avoid >> unnecessary data duplication. >> >> Listing the contents of this hidden directory (named "HFS+ Private Data", >> but with a bunch of non-printing characters preceding the "H") on my Time >> Machine backup volume reveals that it contains 573,127 files. B-trees or no >> b-trees, over half a million files in a single directory makes me nervous. >> >> That feeling is compounded by the most glaring omission in HFS+—and, to be >> fair, many other file systems as well. HFS+ does not concern itself with >> data integrity. The underlying hardware is trusted implicitly. If a few bits >> or bytes get flipped one way or the other by the hardware, HFS+ won't >> notice. This applies to both metadata and the file data itself. >> >> Data corruption in file system metadata structures can render a directory or >> an entire disk unreadable. (For a double-whammy, think about corruption that >> affects the "HFS+ Private Data" directory where every single hard link file >> on a Time Machine volume is stored.) Corruption in file data is arguably >> worse because it's much more likely to go undetected. Over time, it can >> propagate into all your backups. When it's finally discovered, perhaps years >> later when looking at old baby pictures, it's too late to do anything about >> it. >> > > > --- > Lee Larson > [email protected] > > > … we are all in the gutter, but some of us are looking at the stars. — > Oscar Wilde, > Lady Windermere’s Fan > > _______________________________________________ > MacGroup mailing list > Posting address: [email protected] > Archive: > <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_macgroup-40erdos.math.louisville.edu_&d=DwIFaQ&c=OAG1LQNACBDguGvBeNj18Swhr9TMTjS-x4O_KuapPgY&r=F2GFXrjLFqVo3VwvIlo_XYeEiRRjHv15rxcenz7A21woG2aFGcrzndoSsskxfmOs&m=gNdlwOayecsT_E_koKv0ivIAFgIKVF5rmAw3f3Pv-z0&s=5emNS6WNAzvI9IMSRVNQno2WutiXqIWOyDTMGApJrIs&e=> > Answers to questions: <http://erdos.math.louisville.edu/macgroup/> _______________________________________________ MacGroup mailing list Posting address: [email protected] Archive: <http://www.mail-archive.com/[email protected]/> Answers to questions: <http://erdos.math.louisville.edu/macgroup/>
