Mac Mini disconnects Thunderbolt drives, with no apparent reason

Discussion in 'Mac mini' started by shollenbmk, Apr 13, 2017.

  1. shollenbmk, Apr 13, 2017
    Last edited: Apr 13, 2017

    shollenbmk macrumors newbie

    Apr 13, 2017
    Hey Everyone,

    We're having an issue with our new Mac Mini, 64TB G-Tech drive, and 32TB OWC drive. I'll describe it below. Note that the same issue is occurring with both drives, which seems to eliminate either individual drive as the issue.

    We have a Mac Mini on our network, as shared storage for 7 people. The Mac was purchased in 2016, along with the 64TB G-Speed drive (Running in RAID 10, for 32TB of functional space) and a 32TB OWC drive (Used for occasional backups, via CCCloner.) The Mac Mini is maxed-out on processor and 16gigs of RAM, as of 2016.

    About 70% of the time, everything runs well. The storage is fast and reliable. The problem that we get is that our two thunderbolt drives disappear from network sharing, on their own. Someone will connect to the mac mini and find only the Mini's internal drive, no thunderbolt drives. Nobody else will see the Thunderbolt drives either. This seems to only happen when the drives are not in use, as nobody has noticed their transfers being ended mid-transfer. While the thunderbolt drives do not appear on network sharing, they almost always are still available to the Mac Mini, on it's desktop. Also, CCCloner has not had any errors that would suggest it has lost the Thunderbolt drives, suggesting this issue is only relevant to network sharing.

    To solve this, we have to go to the Mac Mini and reboot. This solves the issue about 50% of the time. It often takes multiple reboots before both thunderbolt drives appear on the network. All the while, they typically appear on the Mac Mini's desktop, regardless of their network availability.

    The Mac is set to never sleep, as are all connected drives. We have the Mini restarting on it's own, every weekend. The problems don't seem to appear in any particular time period. Sometimes this happens 4 days after the last reboot, sometimes 2 hours after.

    I'm happy to provide more information. Please let me know whatever you need. So far, I can't seem to find a solution to this. :( We want our thunderbolt drives shared all the time!

    Thank you!

    Edit: Typos
  2. treekram macrumors 65832

    Nov 9, 2015
    Honolulu HI
    I don't have an answer but since no one else has responded maybe what I have observed may be of use.

    I have a 2014 mid-line Mini which has a Monster Digital 240GB Thunderbolt SSD (it's a Thunderbolt 1 device) attached (very rarely is it removed). It has a WiFi connection.

    I connect to the 2014 Mini from my 2012 Mini (wired Ethernet connection which connects via a hub to the latest Airport Extreme which is serving as an extender of the WiFi network - the 2014 Mini is much closer to this Airport Extreme vs. another Airport Extreme which serves as the main router of the WiFi network).

    I connect to the 2014 Mini pretty much exclusively for screen sharing and once activated in the morning, I don't disconnect until I turn off the computers at night. I connect using the Finder and as such and because I have file sharing on, I see drives that are available via File Sharing. Because I don't use File Sharing, I wouldn't necessarily become aware of the Thunderbolt drive becoming disconnected. However, I don't recall ever not seeing the Thunderbolt drive. Certainly today, there was no problem. I'll keep my eye on the File Sharing to see if the Thunderbolt drive disappears.

    I use the standard File Sharing which comes with OSX (using SMB, the preferred option for OSX File Sharing). If you use something else, I think that would be the best place to look.

    Both machines run El Capitan. If you use Sierra, maybe there are issues there.

    There is an option in System Preferences to never put drives to sleep. It sounds like you have done that. I typically do put my drives to sleep when possible however, it is a SSD drive and what that means for an SSD, I have no idea (I presume your drives are HDD's). On my 2012 Mini, I have the NFS daemon running and have never had problems with clients (WiFi) finding the attached HDD's even though the drives are asleep most of the time.

    If you're using WiFi, maybe there's an issue with the router(s). If you mention the OS that the Mini and the clients are using and how your network is setup and the type of file sharing you're using, maybe that will prompt somebody to respond.
  3. shollenbmk thread starter macrumors newbie

    Apr 13, 2017

    Hey Treekram, thank you for the reply. We're all wired to the same network that the Mac is on. Also, our Thunderbolt drives are operating with hard drives. We can dream about SSDs, though. :p

    As for the OS...
    Mac Mini: 10.11.6
    Most Clients: Same, 10.11.6

    We're using AFP... although we've considered switching to SMB. I brought up the idea of switching to SMB, but our Mac tech convinced us to stay on AFP. Thoughts on this, as a possible issue?
  4. treekram macrumors 65832

    Nov 9, 2015
    Honolulu HI
    We have the same Mini model running the same OS (update level the same as well) connected with different Thunderbolt devices. You have a wired network, which is less likely to have issues as compared to the mixed WiFi/wired network that I use. The main difference I can see is that you're using AFP, I'm using SMB.

    I've noticed a couple of things in the days since I wrote my first response. As I mentioned earlier, I really don't use file sharing but for the first time I did navigate down into my Thunderbolt drive from my client computer. When I turned off the Mini with the TB drive, a little window (I haven't seen it before - it's not like the typical OSX dialog box) came up on the client computer saying that the drive was disconnected. So there is some recognition of a disconnect on the TB drive and an effort to inform the client. On another day, when I did not navigate down the TB drive, in selecting the Mini in the finder, I noticed that it had disconnected - but it was no problem to reconnect.

    I'll try using AFP and see if I notice anything. Off the bat, I have noticed that even if AFP only is selected, when I do connect, it says there is one AFP and one SMB client connected (it is my 2012 Mini only that is connected as once I disconnect from the 2012 Mini, the count goes to zero for both AFP and SMB). I don't know what that signifies. I also noticed a quick disconnect in the Finder - something that I haven't seen when using SMB. I was able to reconnect to the 2014 Mini. After changing my preference to AFP only, I did reboot to try to start fresh.

    I think it would be good for you to try SMB and see if the problems go away.

    Also, if your network is crossing over hubs/routers, in a past life, I seem to remember issues that can arise there.
  5. ryguy92000 macrumors regular


    Sep 20, 2014
    Salt Lake City, UT
    You have a lot of variables in this issue. The biggest of which is your trying to utilize the Mini as a NAS. The AFP also runs along the mDNS protocol which can be finicky under untested conditions. I would suggest trying to move the drives to an alternate machine as an experiment to see if there is any change. My guess would be the answer of no. You may need to switch to a full NAS (like a synology) solution.
  6. shollenbmk thread starter macrumors newbie

    Apr 13, 2017

    Thank you both for the replies.

    We haven't changed anything yet, because the mini has suddenly stopped exhibiting the issue. We haven't noticed it since posting this thread. Talk about timing...

    Anyways, we would certainly prefer a legitimate NAS, but came to this mini after long negotiations with IT, on what we are and are not allowed to run. We have to make do with what we have. :/
  7. treekram macrumors 65832

    Nov 9, 2015
    Honolulu HI
    In trying out AFP, after the one disconnect mentioned in my post (no problems recovering from it), I didn't notice any issues. As I mentioned earlier, it might have been a network configuration issue. But that's something that's very difficult for an end-user to diagnose and in my experience, something that network support personnel would put a low priority on solving (not that I would blame them - it could take quite a bit of time with no guarantee of a solution). If it recurs, you should see what people are doing with the shared drives - typical stuff like saving a file, etc. are not likely to cause an issue. But maybe somebody is doing something unusual, using a program which generates a lot of network requests to the Mini. Or a program which uses custom code to access the network drive (typically when a program saves a file, OSX will see it's a network drive take care of that but a program may actually program the network calls itself).

    If you're only using the Mini as a file server, maybe a NAS with multiple network interfaces or other features may be useful, but otherwise, I don't know that it would be worth fighting the battles necessary to get it for what your stated requirements are.

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