Strange ownership issue when login into another Mac on same network

[macstatic]

I have a strange issue regarding my wife's Mac which is connected to the same wired network as my Mac.
I log into her computer (by double-clicking her computer name on the bottom left side of any Finder window where it says "locations"), then enter her username/password. This should give me access to all her files/folders, which is helpful whenever I'm helping her to organize stuff on her computer, but sitting at my own Mac.

Now the strange thing is that whichever file or folder I click on and select "Show info", strangely I am the one who's the owner of that particular file or folder! But if I do the same "Show info" physically from her computer, her name shows up as the owner (as is correct of course). Is this normal?

The reason I ask is because I recently spent some time organizing her photos by merging multiple iPhoto libraries, removing duplicates etc. and creating a new Photos library as a result (using PowerPhotos for all that). I then transferred it over to her Mac via the network and it worked fine over there on her Mac. But when doing a remote backup (using Chronosync/ChronoAgent) and seeing that it appeared to be copying the entire Photos library again, instead of just the few small additions of photos/changes since last time (I've come to understand a Photos library is in fact a folder, not a file as it appears to be), so I did a "Show info" from my Mac and it show "Zero bytes" !!!! While it's in fact 185 GB when doing a "Show info" physically on her Mac.
Can anyone make sense of this?

 

[hobowankenobi]

Historically...using the Get Info box on files shared over the network was not reliable, and for years not even usable. I have not tested this in years, so perhaps this is no longer true. But I can assure you that tweaking file permissions on a network share via the GUI was a bag full of pain for many years. Your description reminds me of the bad old days. I would disregard the network Get Info stuff, unless there is a specific problem you need to solve.

Let's see if someone has specific knowledge of the iPhoto library issue, but I would not be surprised if this is common. Many modern app packages include databases, and/or have extensive caching that can essentially break incremental backups. I have used Chronosync for years, but on Mac file servers...with no Photos or Music or Mail content, so I can't speak to the package issue. If a tool like Chronosync sees the library package as a single file..and it changes...yep, full backup again. I see others discussing it here in more detail.

 

[macstatic]

Thanks for explaining.
As we speak I'm doing another remote Chronosync backup of my wife's Mac, and it looks like her Photos library is being backed up in full yet once again (the same goes for the other Photos and iPhoto libraries which I used as a source for merging it all into one Photos library -these are all on her Mac as well). What's strange is that neither I nor her have opened any of these libraries since last backup, so there shouldn't be any changes made to them!

But I'm going to look into this matter in more detail, so after having completed this Chronosync backup I want to do a "get info" of the various Photos and iPhoto libraries (to see their file-sizes, modification dates etc.), then attempt another Chronosync backup. In theory at least it shouldn't back those libraries up again, but we'll see.

What's stranger is that her Time Machine backups don't seem to do this as they don't take much time to do each backup (we have a permanently attached USB-3 drive attached to her Mac Mini, so it lives its own life, doing backups regularly). I should probably compare the time it takes to backup up (by clicking "Back up now" in the Time Machine icon in the menu-bar) with the time it takes to do another Chronosync backup.

 

[JoeG4]

File sharing protocols are rather crap with permissions. That said, it's usually UID based. If you both created the first and only account on your computers, you probably both have uid 501. That's why you're both seeing yourselves as owner of the files.

(If you're wondering, open a terminal window and type in "id -u")

 

[macstatic]

File sharing protocols are rather crap with permissions. That said, it's usually UID based. If you both created the first and only account on your computers, you probably both have uid 501. That's why you're both seeing yourselves as owner of the files.

(If you're wondering, open a terminal window and type in "id -u")

If I do that (id -u) on my own Mac I get 503.
For checking my wife's UID, do I have to do the same by physically being on her Mac?
I don't know if I did it correctly, but since her Mac was switched on, I tried logging into her computer from the Terminal app on my own Mac by entering: login username (replacing "username" with my wife's username of course, then entering her login password when asked),
and following that I entered id -u which gave me the nuber 502.

Both computers have multiple user accounts.

 

[JoeG4]

If I do that (id -u) on my own Mac I get 503.
For checking my wife's UID, do I have to do the same by physically being on her Mac?
I don't know if I did it correctly, but since her Mac was switched on, I tried logging into her computer from the Terminal app on my own Mac by entering: login username (replacing "username" with my wife's username of course, then entering her login password when asked),
and following that I entered id -u which gave me the nuber 502.

Both computers have multiple user accounts.

Heh never saw the login command before. Using "login" on your own computer just switches the user in that terminal window. If you wanted to connect to her computer via terminal, you'd need to enable 'remote login' on her computer (aka ssh) and then use something like ssh hername@her-computer-name.local

Anyway the user number starts with 501 (first user created), 502 (second user created), and so on.

If your user account is 503 on your computer, and her user account is 503 on her computer, it makes sense to me thta your file sharing is acting this way.

 

[macstatic]

Thanks for explaining -I didn't know that.
I checked again, physically on her computer (using the Terminal app) and id -u returned 501.
And I re-checked on my own computer, which is still 503.
Does this mean the problem is elsewhere, and not related to the UID?

I also did a "get info" of the various iPhoto and Photos libraries on her computer, and to my surprise they were modified today. That's very strange, because neither her or I have opened up the libraries or used Photos (or iPhoto) at all today.

 

[Fishrrman]

OP wrote:
"I checked again, physically on her computer (using the Terminal app) and id -u returned 501.
And I re-checked on my own computer, which is still 503.
Does this mean the problem is elsewhere, and not related to the UID?"

What user ID# an individual account has, depends on WHEN that account was created on the Mac in question.

When you first set up a Mac, if you create an account using the setup assistant, it will always have the "501" ID -- because it was the first account created.

If you create a second account, it will have the 502 ID.

If you were to then use migration assistant to move an account from another Mac, it will come over as the 503 ID -- even if it was the ONLY account on the other Mac (having the ID 501).

So if the user ID numbers don't "match up" when "networking" from one Mac to another, it's probably not that important. What IS important is that the accounts "work" without other problems, and that you can still access them as needed.

 

[macstatic]

Yes, everything else appears to work except this strange problem.
But.... I might have discovered the cause:
I noticed that the two Photos libraries that were on her Mac (not the iPhoto libraries too, as I mistakingly pointed out earlier) had their modification dates changed to today, which doesn't make sense since neither of us had accessed the Photos app yesterday or today. So I tried to open/close all sorts of things to see if that would make the modification date change again, such as initiating a Time Machine backup, but no go.

Suddenly I noticed the modification dates of both Photos libraries changed again and I immediately opened Activity Monitor and sorted CPU activity by %CPU. I noticed that two familiar apps were running: photoanalydisd and photolibraryd. I had read about them in the past and it occured that they were probably running some background task, which is why the libraries got their modification dates changed. That probably makes sense, right?

So if that's the case, does anyone know what they're doing? I thought they would analyze all the photos in a library until done, then leave it alone (until new photos will be added/deleted/edited etc.), but maybe that's not the case.
It's a huge pain that the entire 185 GB library has to be backed up again and again, even though no changes have been made (the Photos app hasn't even been accessing the library).

 

[gilby101]

I noticed that two familiar apps were running: photoanalydisd and photolibraryd. I had read about them in the past and it occured that they were probably running some background task, which is why the libraries got their modification dates changed. That probably makes sense, right?

Yes. They are active at least daily.

For Chronosync, you can modify package handling.

Package handling can be Standard, Merge or Dissect.

I have "merge", which means that CS will only copy changes using some knowledge of how packages work. "Standard" is likely the safest.

See the CS manual https://downloads.econtechnologies.com/manuals/CS_Manual.pdf which says:
"Package Files
In macOS, packages are simply folders disguised to look like single files when presented in
Finder. The most common examples are applications. Within an application’s package file, you
may find property lists, icons, string files, resources and any other supporting files necessary to
run the application.
By default, ChronoSync presents and treats packages as single files, not folders. Thus, when
ChronoSync detects a package file has changed, it really means that some file within the
package has changed and that when ChronoSync copies a package file, it is actually copying a
folder and all its contents.
If you wish to change how ChronoSync handles package files, make a selection in the “Package
Handling” menu under “Special File/Folder Handling” in the Options panel. ’Standard’ treats
packaged files as a whole, 'Merge' attempts to merge changes of the packaged files, and
'Dissect' treats packaged files as regular folders and examines their content.
In addition to synchronizing package files, you also have the option of selecting a package as
one of your targets. This is useful for cases where packages are used to store massive amounts
of data, such as Photos libraries and such. To do this, choose the “Allow package selection”
option in the file selection sheet.
More information on package files and how ChronoSync handles them, check out our tech note
‘The Package Conundrum’."

Also, am I right is understanding you are using ChronoAgent on the other Mac? It allows you to map file ownership by username (not UIDs) from one Mac to the other. CS with CSA is so much better than CCC for sync between Macs.

 

[macstatic]

Yes. They are active at least daily.

For Chronosync, you can modify package handling.

View attachment 2360919
Package handling can be Standard, Merge or Dissect.

I have "merge", which means that CS will only copy changes using some knowledge of how packages work. "Standard" is likely the safest.

Thanks for explaining! This was news to me, but fortunately there appears to be a solution.
Apart from Photos libraries, are there other files that inhibit the same sort of issues?
I assume the foolproof method would be to select "merge", but being slower I guess it's best just to know about these issues and change it to "merge" once you notice that it tries to backup the same file again and again even if you know there haven't been any changes (like in my case with the Photos libraries).
Obviously, Time Machine knows about this and doesn't re-copy the same Photos library when I haven't touched it.

Also, am I right is understanding you are using ChronoAgent on the other Mac? It allows you to map file ownership by username (not UIDs) from one Mac to the other. CS with CSA is so much better than CCC for sync between Macs.

Correct. Yes, I installed Chronosync Agent on her Mac, but do backups remotely from my own Mac running Chronosync.
I've used Chronosync for years (but keep learning new things about it all the time), but haven't used Chronosync Agent for very long and may have messed around with things I didn't know about.
Is the "Ownership by username" setting found within the task file on my Mac, or the settings in Chronosync Agent on my wife's Mac?

EDIT: I checked my settings for my wife's Chronosync backup document (residing on my Mac and connecting through her Mac's Chronosync Agent) and it appears "Merge" is already enabled. Under "Options"-"Special files/folder handling" it's set to Basic, but it clearly says "Merge" within package handling, so it's strange that it still attempt to bacup the entire Photos library each time:

As for the file ownership by username and not UUID; I could't find it in neither Chronosync nor Chronosync Agent. Where's that setting?

 

[gilby101]

Apart from Photos libraries, are there other files that inhibit the same sort of issues?

Anything that is a package. E.g. Pages documents, applications - but these are all small. It is only with large packages that you might want to optimise.

Time Machine knows about this and doesn't re-copy the same Photos library when I haven't touched it.

TM also knows to copy only essentials - it does not backup all the library. As a result, if you restore a Photos library, there is a recovery phase the first time you open the recovered library. I suspect it also rebuilds the search indexes in the background.
Given that Apple is forever tweaking the internals of Photos libraries, it is probably wise that other products (e.g. CS and CCC) try to backup the complete library.

Is the "Ownership by username" setting found within the task file on my Mac, or the settings in Chronosync Agent on my wife's Mac?

As for the file ownership by username and not UUID; I could't find it in neither Chronosync nor Chronosync Agent. Where's that setting?

Chronosync > Settings > Connections. Open the ChronoAgent connection and use the Mappings tab. I use this to map my wife's username on her Mac to my username on my Mac. This just is for a one way sync from her's to mine before backup to the cloud.

Under "Options"-"Special files/folder handling" it's set to Basic, but it clearly says "Merge" within package handling, so it's strange that it still attempt to bacup the entire Photos library each time:

Merge seems to be the default. Maybe time to talk to CS support.

 

[macstatic]

I don't know what I've done, but I must have done something right (or have gotten a new understanding of this) because it appears to back up the photos libraries faster than before.
Thing is, I was probably expecting Chronosync to quickly just pop up the name of the file in question,then move on to the next file (in the progress window which you can see when a Chronosync task is open and running), but instead it appears to analyze the file, so it takes a while, but apparently not as slow as actually copying the entire Photos library over to the backup drive again.
But... I have noticed that it does take a lot longer to back up a Photos library when new photos/videos have been added compared to say backing up a folder with the same photos/videos in a the Finder.

I'm still at loss to what I've done to make this work (maybe it worked all along!), but it's probably the "Package handling: merge" feature (shown in your screenshot in a previous posting). Then again that was on by default, so I'm a little confused.... Maybe it just needed resetting or something. Computers sometimes do unexplainable things

I need to look into that "Ownership by username" feature in your previous posting as I didn't fully understand that, but for no it appears that Chronosync doesn't any longer copy the entire Photos libraries, but still has to spend a while scanning through its content.
Not ideal, but that's Apple's fault, not Chronosync's.