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  • Odd Time Machine Behaviour

    From RJH@patchmoney@gmx.com to uk.comp.sys.mac on Mon Aug 3 01:29:38 2026
    From Newsgroup: uk.comp.sys.mac

    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for several incremental backups. Last backup failed - 'insufficient space'. By my
    reckoning it shouldn't need that much space as there's only about 300GB of
    data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and set about a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25% into the backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much larger than the disk? The disk is showing 700GB of 1TB used. 140GB of that is Photos, excluded from the TM backup. So even if it backed up everything it should only need 560GB - not the 1.4TB it seems to want.
    --
    Cheers, Rob
    Sheffield, UK
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From David Kennedy@davidkennedygm@gmail.com to uk.comp.sys.mac on Mon Aug 3 06:04:48 2026
    From Newsgroup: uk.comp.sys.mac

    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for several
    incremental backups. Last backup failed - 'insufficient space'. By my reckoning it shouldn't need that much space as there's only about 300GB of data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25% into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much larger than the disk? The disk is showing 700GB of 1TB used. 140GB of that is Photos,
    excluded from the TM backup. So even if it backed up everything it should only
    need 560GB - not the 1.4TB it seems to want.

    Because Time Machine is keeping earlier information? So it may have decided that it needs more than the 300Gb available?
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From Graham J@nobody@nowhere.co.uk to uk.comp.sys.mac on Mon Aug 3 08:14:18 2026
    From Newsgroup: uk.comp.sys.mac

    David Kennedy wrote:
    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for
    several
    incremental backups. Last backup failed - 'insufficient space'. By my
    reckoning it shouldn't need that much space as there's only about
    300GB of
    data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and
    set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25%
    into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much
    larger
    than the disk? The disk is showing 700GB of 1TB used. 140GB of that is
    Photos,
    excluded from the TM backup. So even if it backed up everything it
    should only
    need 560GB - not the 1.4TB it seems to want.

    Because Time Machine is keeping earlier information? So it may have
    decided that it needs more than the 300Gb available?

    I doubt it.

    The OP says that this is a "new, fresh, TM backup". So there is no
    earlier information for it to keep!
    --
    Graham J
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From Alan B@alanrichardbarker@gmail.com.invalid to uk.comp.sys.mac on Mon Aug 3 07:52:33 2026
    From Newsgroup: uk.comp.sys.mac

    On 2026-08-03, Graham J <nobody@nowhere.co.uk> wrote:
    David Kennedy wrote:
    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for
    several
    incremental backups. Last backup failed - 'insufficient space'. By my
    reckoning it shouldn't need that much space as there's only about
    300GB of
    data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and
    set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25%
    into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much
    larger
    than the disk? The disk is showing 700GB of 1TB used. 140GB of that is
    Photos,
    excluded from the TM backup. So even if it backed up everything it
    should only
    need 560GB - not the 1.4TB it seems to want.

    Because Time Machine is keeping earlier information? So it may have
    decided that it needs more than the 300Gb available?

    I doubt it.

    The OP says that this is a "new, fresh, TM backup". So there is no
    earlier information for it to keep!

    Maybe it depends on whether the % refers to just the amount of data copied, the estimated
    time taken so far or some combination of the two or even something else? For instance, do
    lots of small files take longer to backup than, say, one large file of the same total size
    as a set of small files?
    --
    Cheers, Alan
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From RJH@patchmoney@gmx.com to uk.comp.sys.mac on Mon Aug 3 08:01:03 2026
    From Newsgroup: uk.comp.sys.mac

    On 3 Aug 2026 at 08:52:33 BST, Alan B wrote:

    On 2026-08-03, Graham J <nobody@nowhere.co.uk> wrote:
    David Kennedy wrote:
    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for >>>> several
    incremental backups. Last backup failed - 'insufficient space'. By my
    reckoning it shouldn't need that much space as there's only about
    300GB of
    data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and
    set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25%
    into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much
    larger
    than the disk? The disk is showing 700GB of 1TB used. 140GB of that is >>>> Photos,
    excluded from the TM backup. So even if it backed up everything it
    should only
    need 560GB - not the 1.4TB it seems to want.

    Because Time Machine is keeping earlier information? So it may have
    decided that it needs more than the 300Gb available?

    I doubt it.

    The OP says that this is a "new, fresh, TM backup". So there is no
    earlier information for it to keep!

    Indeed.

    Maybe it depends on whether the % refers to just the amount of data copied, the estimated
    time taken so far or some combination of the two or even something else? For instance, do
    lots of small files take longer to backup than, say, one large file of the same total size
    as a set of small files?


    The backup failed overnight - couldn't copy Whatsapp files. So I've excluded the Whatsapp container files.

    Trying again - notification saying '56% done - 2GB copied' after about 5 minutes. All very odd.
    --
    Cheers, Rob
    Sheffield, UK
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From Alan B@alanrichardbarker@gmail.com.invalid to uk.comp.sys.mac on Mon Aug 3 08:58:58 2026
    From Newsgroup: uk.comp.sys.mac

    On 2026-08-03, RJH <patchmoney@gmx.com> wrote:
    On 3 Aug 2026 at 08:52:33 BST, Alan B wrote:

    On 2026-08-03, Graham J <nobody@nowhere.co.uk> wrote:
    David Kennedy wrote:
    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for >>>>> several
    incremental backups. Last backup failed - 'insufficient space'. By my >>>>> reckoning it shouldn't need that much space as there's only about
    300GB of
    data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and >>>>> set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25% >>>>> into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much >>>>> larger
    than the disk? The disk is showing 700GB of 1TB used. 140GB of that is >>>>> Photos,
    excluded from the TM backup. So even if it backed up everything it
    should only
    need 560GB - not the 1.4TB it seems to want.

    Because Time Machine is keeping earlier information? So it may have
    decided that it needs more than the 300Gb available?

    I doubt it.

    The OP says that this is a "new, fresh, TM backup". So there is no
    earlier information for it to keep!

    Indeed.

    Maybe it depends on whether the % refers to just the amount of data copied, >> the estimated
    time taken so far or some combination of the two or even something else? For >> instance, do
    lots of small files take longer to backup than, say, one large file of the >> same total size
    as a set of small files?


    The backup failed overnight - couldn't copy Whatsapp files. So I've excluded the Whatsapp container files.

    Trying again - notification saying '56% done - 2GB copied' after about 5 minutes. All very odd.

    Do you have another drive connected externally to your Mac? TM will
    try to backup such a drive unless you exclude it. BTW apologies for
    my over length lines in my first follow-up1
    --
    Cheers, Alan
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From RJH@patchmoney@gmx.com to uk.comp.sys.mac on Mon Aug 3 15:47:31 2026
    From Newsgroup: uk.comp.sys.mac

    On 3 Aug 2026 at 09:58:58 BST, Alan B wrote:

    On 2026-08-03, RJH <patchmoney@gmx.com> wrote:
    On 3 Aug 2026 at 08:52:33 BST, Alan B wrote:

    On 2026-08-03, Graham J <nobody@nowhere.co.uk> wrote:
    David Kennedy wrote:
    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for >>>>>> several
    incremental backups. Last backup failed - 'insufficient space'. By my >>>>>> reckoning it shouldn't need that much space as there's only about
    300GB of
    data - I've excluded Photos for example.

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and >>>>>> set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25% >>>>>> into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much >>>>>> larger
    than the disk? The disk is showing 700GB of 1TB used. 140GB of that is >>>>>> Photos,
    excluded from the TM backup. So even if it backed up everything it >>>>>> should only
    need 560GB - not the 1.4TB it seems to want.

    Because Time Machine is keeping earlier information? So it may have
    decided that it needs more than the 300Gb available?

    I doubt it.

    The OP says that this is a "new, fresh, TM backup". So there is no
    earlier information for it to keep!

    Indeed.

    Maybe it depends on whether the % refers to just the amount of data copied, >>> the estimated
    time taken so far or some combination of the two or even something else? For
    instance, do
    lots of small files take longer to backup than, say, one large file of the >>> same total size
    as a set of small files?


    The backup failed overnight - couldn't copy Whatsapp files. So I've excluded >> the Whatsapp container files.

    Trying again - notification saying '56% done - 2GB copied' after about 5
    minutes. All very odd.

    Do you have another drive connected externally to your Mac? TM will
    try to backup such a drive unless you exclude it.

    No, nothing else.

    It's finally finished - 700GB. Which is considerably greater than the sum of the parts. I'll probably do a fresh install come the next OS. I've over a decade of assorted cruft that could do with clearing . . .

    BTW apologies for
    my over length lines in my first follow-up1

    No probs :-)
    --
    Cheers, Rob
    Sheffield, UK
    --- Synchronet 3.22a-Linux NewsLink 1.2
  • From Bruce@07.013@scorecrow.com to uk.comp.sys.mac on Mon Aug 3 22:25:24 2026
    From Newsgroup: uk.comp.sys.mac


    On 03/08/2026 02:29, RJH wrote:
    I've been using a 700GB of a 1TB SSD as a TM disk for a year or so for several
    incremental backups. Last backup failed - 'insufficient space'. By my reckoning it shouldn't need that much space as there's only about 300GB of data - I've excluded Photos for example.

    Apple recommend using a storage device at least twice the size of the
    device you're backing up.
    <https://support.apple.com/en-us/104984>

    But hey, life goes on so I substituted a 4TB HDD for the TM disk and set about
    a new, fresh, TM backup. That was 12 hours ago and it's 350GB and 25% into the
    backup.

    The SSD on the Mac is only 1TB. How is it that the backup is so much larger than the disk? The disk is showing 700GB of 1TB used. 140GB of that is Photos,
    excluded from the TM backup. So even if it backed up everything it should only
    need 560GB - not the 1.4TB it seems to want.

    Elbow room to work out what it needs to do? Hard to say.

    How are you excluding photos? And are you sure that there isn't an old
    copy of Photos in the backup even if you aren't currently backing them
    up? (Although it should have purged any old copies them to make space as
    it started to run out.)


    Later, on 03/08/2026 16:47, RJH wrote:
    It's finally finished - 700GB. Which is considerably greater than the sum of >> the parts. I'll probably do a fresh install come the next OS. I've over a
    decade of assorted cruft that could do with clearing . . .

    I find it oddly coincidental that the original backup size and the new
    backup size are the same. Are you sure photos are being excluded? Are
    you sure of your file size calculations? (Remembering that small files
    take up more size than they actually are due to needing at least one
    disk block?)
    --
    Bruce Horrocks
    Hampshire, England
    --- Synchronet 3.22a-Linux NewsLink 1.2