El Capitan Server 5.1 network file sharing randomly drops out and files becomes inaccessible

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Level 1

8 points

El Capitan Server 5.1 network file sharing randomly drops out and files becomes inaccessible

Hi, I look after a small office network consisting of a Mac Mini server (El Capitan, Server 5.1) and about 5 Mac Mini clients (all on Yosemite I think).

They've been having problems with network shared files on the server randomly "dropping out" and becoming inaccessible. I saw this myself earlier when logging in to a client system and navigating to the server shared folder, and I was just presented with an empty folder. No error message or indication that anything was wrong, except that I know there's thousands of files there and they wouldn't appear. I tried then browsing to the other shared folder on the server (time machine backups), and again, just an empty folder. Then after about 5 minutes of clicking about, it all suddenly comes back to life and the shared files appear. When this drop-out happens, the internet still functions perfectly on both the client and server systems, and each one can ping the other. It's just the actual file sharing that seems to be the problem.

Also Time Machine backups from the clients have been failing, probably for similar reasons. When the problem was reported to me, none of the Time Machine backups had run for months. I went to each one and re-selected the target network drive, and they started running again, but they've been moving extremely slowly and keep dropping out (for example, one system might back up roughly 1GB of data over an hour and then stop running until the next scheduled backup, which then might work or might fail, etc, and there's easily 50-100GB of data that needs backing up on each system).

When the file sharing drops out and becomes inaccessible to one client, the other clients can still browse and access shared files without problem. It seems to affect all clients equally (as in, everyone reports that they are experiencing this problem) but it doesn't hit them all simultaneously, and lately they've been working around it by asking the person working at the desk next to them "can you go on the server, access this document, and email it to me please?" which is a ridiculous state of affairs!

All of this seemed to start when I first ran an upgrade on the server. It was previously running Lion and this caused a problem with some other software we wanted to install (Livedrive cloud backup, which itself then caused other problems so is now deleted), so I ran the update to Yosemite and I think the problem with the file sharing started there. Certainly that appears to be approximately when the Time Machine backups started failing. However they didn't report the issues for a long time so I can't be certain. I've since updated the server to El Capitan and the latest Server 5.1 in an attempt to get this sorted and it doesn't seem to have helped. I haven't yet updated the clients to El Capitan but it's certainly a consideration.

More info:

All the physical boxes are Mac Mini 2012, the server has 4GB of RAM, with a system SSD drive and a large mechanical drive, and the clients between 2-4GB RAM each.

They're all connected up using a gigabit ethernet switch (Netgear) and cat5e cabling, and there's a Netgear internet router also connected up. The router is handling DNS/DHCP, the server is on a static IP and only handles file sharing, caching, and time machine backups.

All the client users are defined on the server in "users" and are all in a group which has full read/write access to the shared folder, which is set for AFP and SMB.

Going to "connected users" on the server file sharing tab, reveals that most of the systems are connecting via AFP however one system for reasons I do not know, is connecting over SMB. This system also does not really use the shared files much (they access a couple of files once at the end of the working day, and that is it) so I do not know if they are experiencing the same problems. However my understanding is that Apple-to-Apple sharing works at its best over AFP, and Time Machine has to run over AFP anyway, so I've not yet tried disabling AFP on the shared files folder, forcing everyone to use SMB, to see if that changes anything.

At this point I've tried everything I know and have run out of options - I'd really appreciate some help in getting this problem resolved. Thanks!

Mac mini, OS X El Capitan (10.11.5)

Posted on Jun 3, 2016 4:09 AM

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Answer 1

Jun 3, 2016 3:27 PM in response to Statick777

I had similar behavior come from a server I built recently when I forgot set the sleep setting to Never during initial set up. Just in case, check your Energy Saver settings and make sure your server isn't permitted to sleep.

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Answer 2

Statick777 Author

Level 1

8 points

Jun 3, 2016 6:52 PM in response to Erich Wetzel

As I said, when the sharing drops out, those files are still accessible from other clients on the network, and I can still access the internet from both systems, and they can ping each other successfully as well. Therefore, it's not gone to sleep.

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Answer 3

TeenTitan

Level 4

2,640 points

Jun 3, 2016 10:04 PM in response to Statick777

Is this over wifi or ethernet?

Assuming it's ethernet, have you verified the wifi is off on all computers? Is blue tooth off for all the computers?

On one of the computers that's having the issue, have you tried configuring the client computer not to sleep? if so, does it still have the issue?

On one of the client computers that's having the issue. Have you tried leaving ping running to the server? If so, when it has the issue, do you see ping dropping out at all?

Does the issue only happen over AFP? or does it happen over SMB too?

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Answer 4

Statick777 Author

Level 1

8 points

Jun 4, 2016 5:07 AM in response to TeenTitan

Wi-Fi and Bluetooth are disabled all over.

Everything is cabled up to a gigabit ethernet switch. I can ping from the client to the server, and from the server to the client, when the problems happen and network shares are unavailable. The client computers are all in use all the time and do not sleep (not sure how I'd see a networking problem from a computer which was asleep anyway). When monitoring this problem, I am logged in to both client and server simultaneously, watching both.

As far as I can tell the problem happens on both AFP and SMB however I can't verify this currently. It's definitely happening on AFP but I'm not sure about SMB. Is there a way to force a client to connect over SMB without disabling AFP entirely on the server?

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Answer 5

Leopardus

Level 4

1,303 points

Jun 4, 2016 8:25 AM in response to Statick777

If you've closely followed the history of Server, you would have noticed the changes and the effects that it has on our work. This is a manifestation of one of them. But don't despair, there are some exciting features hidden which can be useful for some deployments. These features are available through the use of Serveradmin. Others are available, using a similar process.

To see what options are available for AFP simply use in Terminal the command:

sudo serveradmin settings afp

Interesting to note and use for instance:

sudo serveradmin settings afp:loginGreeting = ""

sudo serveradmin settings afp:idleDisconnectMsg = ""

both of which you can populate with an appropriate message. But that will not solve your problem as yet, it will only make it visible to the clients (users), what is actually happening 'under the hood' as the real problem lies with the 'idle disconnect' and the lack of logging out from the shares/server.

We can see details of our shares by entering

sudo serveradmin settings sharing

The ability to drop clients/workers who forget, or too lazy to disconnect is the difference between a perfectly functional server on one hand or one that may struggle with idle connections. We observe that in enterprises and small business deployments, people simply almost never shut off their Macs. The stability has been so good in the past, and we are spoilt by that too in the present, that some users will just leave their Macs on for months if you let them. That causes some unnecessary strain on the server and client Macs then cannot refresh their share information.

To prevent this situation, i.e. to disconnect these shares when the users are idle, you can enable the IdleDisconnect feature in server admin for AFP. You can set your own duration of course, for what is applicable in your organisation.

Make a backup of your server settings, using a utility like Bender or something similar.

To enable an IdleDisconnect with a one hour idle disconnect, a 30 min logout time and no reconnect flag, you can use these settings in Terminal:

sudo serveradmin settings afp:idleDisconnectOnOff = yes

sudo serveradmin settings afp:idleDisconnectTime = 1

sudo serveradmin settings afp:reconnectTTLInMin = 30

sudo serveradmin settings afp:reconnectFlag = none

You have to restart AFP for the changes to take effect. Enabling these or similar settings will cause the server to close these idle connections and have resources free and available if and when share updates should take place.

HTH

Leo

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Answer 6

Jun 4, 2016 4:28 PM in response to Statick777

I read and understand what you said. However I did not say my server went to sleep or was asleep. I said that my server exhibited similar behaviors to yours. My users had almost identical problems to what you described. It was a shot in the dark for sure. Sorry to take up your time...

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Answer 7

Statick777 Author

Level 1

8 points

Jun 6, 2016 6:46 AM in response to Leopardus

currently the idle disconnect time is 10 hours and the reconnect ttl is 1440 minutes (24 hours)

I shall update the settings as you suggest. to restart AFP is that simply a case of turning file sharing off then on again in the Server app?

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Answer 8

Leopardus

Level 4

1,303 points

Jun 6, 2016 6:58 AM in response to Statick777

I would certainly make it shorter, could be a disconnect time of around 4 to 6 hours and a reconnect in the region of around 14 to 16 hours.

The average worker would (should) have a break and at least go home and sleep sometimes. But, having said that, it is your environment and you will have to make a decision on that.

You could do that or use the stop / start command in terminal.

HTH

Leo

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Answer 9

Leopardus

Level 4

1,303 points

Jun 6, 2016 12:04 PM in response to Statick777

Statick777 wrote:

...... to restart AFP is that simply a case of turning file sharing off then on again in the Server app?

My apologies: I was in too much of a hurry, and did't fully read the implications.

My preference would be to use Terminal or to restart the server again, after hours. I would publish a circular for everybody to shut down their Macs for the night, so that we all start from a clean slate, and re-evaluate the situation after a couple of days or a week.

Did I mention backup?

HTH

Leo

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Answer 10

Statick777 Author

Level 1

8 points

Jun 6, 2016 12:35 PM in response to Leopardus

thanks, we have Time Machine running on the server to an external disk, and I've verified that it's actually working

I'll restart the server now, and email them to ensure the clients are all restarted in the morning

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Answer 11

Statick777 Author

Level 1

8 points

Jun 7, 2016 6:35 AM in response to Statick777

edit: deleted post

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Answer 12

Aug 11, 2016 2:39 PM in response to Statick777

Hey guys... this is an ugly problem... I have a few Macs at home, and a few at the office, and even between Macs running the same OS, 10.11, this is a problem. I also have a Synology NAS...one at home and one at the office.... same problem.... can connect sometimes... but not all times.. This is clearly a Client Side Problem.

Here's the solution.

SMB://xxxxx

That's right... turn ON Windows File Sharing on File Servers you wish to reach, use the Connect To Server window under the Finders' Go Window, and this should solve your problems. Apparently AFP is on its way out.... From what I understand AFP won't even work with the release of 10.12, so while all of the previous iterations of the MacOS works with SMB as either the client or the server, disabling it under 10.12 as both a client an server option shouldn't be a problem.

As to WHY Apple is doing this, I think the reason is clear. They only want you to connect to servers in the cloud, and no longer with to support local area networking. Yeah, I know... call me crazy... but wait a few years and you'll see exactly what I mean.

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