Time machine disk not found

[Megahurtz]

I've been running Time Machine for many many months using a USB drive attached to my GT-AX6000 to back up to. After not using my computer much lately, I recently discovered that no backups had occurred for the past two weeks. I thought that might have been because I didn't use my computer during that time, but when I tried to manually initiate a backup it failed to connect to the disk.

I have restarted both my computer and router multiple times. Turned Time Machine off/on in the router settings multiple times. I tried removing the TM disk from my computer's settings intending to re-add it, but now it can't even discover the disk. I tried to add it to a different MacBook and that also couldn't find the disk.

Here is what I see when TM starts up on the router:

rc_service: httpd 2969:notify_rc restart_timemachine
Jun 30 15:17:02 Timemachine: daemon is stopped
Jun 30 15:17:02 Timemachine: User select disk start TimeMachine
Jun 30 15:17:02 avahi-daemon[22262]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
Jun 30 15:17:02 afpd[22270]: Couldn't open extension maping file /usr/etc/extmap.conf
Jun 30 15:17:02 afpd[22270]: Couldn't load extension -> type/creator mappings file "/usr/etc/extmap.conf"
Jun 30 15:17:02 cnid_metad[22273]: Couldn't open extension maping file /usr/etc/extmap.conf
Jun 30 15:17:02 cnid_metad[22273]: Couldn't load extension -> type/creator mappings file "/usr/etc/extmap.conf"
Jun 30 15:17:02 cnid_metad[22273]: CNID Server listening on localhost:4700
Jun 30 15:17:02 afpd[22270]: Netatalk AFP/TCP listening on 192.168.1.1:548
Jun 30 15:17:05 Timemachine: daemon is started
Jun 30 15:17:05 avahi-daemon[22314]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
Jun 30 15:17:05 avahi-daemon[22314]: Alias name GT-AX6000: avahi_server_add_cname failure: The requested operation is invalid because redundant

From what I've read those extmap and avahi cname messages are normal. Any ideas?

 

[sfx2000]

Try to mount the shared folder via Finder...

If Finder can't find the share, you need to sort out the mount within AsusWRT.

---------

FWIW - it's really hard to recommend using TM with any router's shared folder implementation - Netatalk/AFP has been deprecated now for some time, and on Apple Silicon, it's not supported at all.

This even applies to Apple's Airport Extreme and TimeCapsule devices as they have not had updates in years now...

The best backup destination for TimeMachine is always direct attached storage, hands down...

For Network based backup on TimeMachine - the best solution there is another Mac with Shared Folders...

TimeMachine has evolved much - moving from AFP over to SMB/CIFS and the SparseBundle Internals from HFS+ over to APFS - Apple doesn't document much about what they do with TM, so third party solutions are basically reverse engineered.

I use a Mac Mini 2018 Intel Core i5 with an 8TB external drive over USB3 to back up all the Macs on my LAN - that's 6 Macs, and the Mini also support my Plex server along with Apple's Content Cache server, which caches downloads across on the devices for Apple SW updates along with iCloud and other services...

It does those services despite me also having two NAS boxes - one from QNAP and the other from Synology...

Yeah, running a Mac Mini is a bit of a luxury - but Mini's can be reasonably priced - for TM/Content Caching, you don't need the latest MacOS, so this opens up some options...

Here's a starter - I've done a number of buys from them, and they've always been good...

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[Megahurtz]

I spent a lot of time fiddling with this and got nowhere. SMB share worked no issue. I finally caved in and reset the router to factory settings. After setting the wifi networks back up and turning on wan aggregation, the first thing I did was reconfigure Time Machine. Worked right away, no issues running a backup

I wish I could have fixed whatever went wrong instead, but I'm slowly re-doing all of my settings. At least backups are working again!

 

[Megahurtz]

Aaaaaand I'm right back to where I started. After three successful backups yesterday, once I had finished redoing all of my router settings I noticed this morning that I was back to not being able to connect to the TM disk.

I have a hunch it may be related to either my VPN settings or my DDNS configuration. I'm not sure how either of those would affect it, but they were the last things I set up yesterday. I just reset the router again and did a minimal configuration of wifi and DNS settings. I've got a backup running now. I'll try setting up DDNS and then VPN after that and try to catch where it breaks.

 

[OzarkEdge]

it breaks.

Don't take this the wrong way... when it comes to backups, if it doesn't perform reliably 100% of the time, then you need a different backup solution. This requirement has always stopped me from relying on storage connected to router USB ports.

OE

 

[sfx2000]

Don't take this the wrong way... when it comes to backups, if it doesn't perform reliably 100% of the time, then you need a different backup solution. This requirement has always stopped me from relying on storage connected to router USB ports.

I agree - I suspect part of the challenge is that Asus hasn't done much with the TM feature in years, and Apple has moved on - TM client side is a moving target, and with APFS and the move to TM over SMB, perhaps these changes are too much for the older implementation on most routers...

Even with SMB, mac's talk SMB3 natively thru their stack, so connecting to older SMB1/2 servers could be problematic - remember, Apple doesn't use Samba any more, they use their own stack after Samba moved to GPLv3 a few years back.

 

[toaruScar]

mDNS name drifting on ZenWiFi XT8

I've got this issue where the mDNS name of my router keeps changing or -should I say- increasing. What do I mean by "mDNS name"? One of my router's hostname is set to `ZenWiFi_XT8-Main`, so it's reachable at `zenwifi_xt8-main.local`, and this ".local" name is the mDNS name. What is the...

www.snbforums.com

Check if the router has changed its mDNS name because of a "conflict".

 

[sfx2000]

mDNS name drifting on ZenWiFi XT8

I've got this issue where the mDNS name of my router keeps changing or -should I say- increasing. What do I mean by "mDNS name"? One of my router's hostname is set to `ZenWiFi_XT8-Main`, so it's reachable at `zenwifi_xt8-main.local`, and this ".local" name is the mDNS name. What is the...

www.snbforums.com

Check if the router has changed its mDNS name because of a "conflict".

This goes a bit towards Asus not having a full mDNS/Avahi implementation...

@RMerlin - we discussed this some time back about bringing in libnss-mdns into your build at least - this becomes even more important as Apple Silicon Macs do not use Netatalk at all for service/device discovery...

 

[RMerlin]

This goes a bit towards Asus not having a full mDNS/Avahi implementation...

@RMerlin - we discussed this some time back about bringing in libnss-mdns into your build at least - this becomes even more important as Apple Silicon Macs do not use Netatalk at all for service/device discovery...

As far as I remember, people at the time indicated that libnss would only serve a purpose if the router itself was trying to resolve something, not for the clients themselves trying to resolve something.

 

[sfx2000]

As far as I remember, people at the time indicated that libnss would only serve a purpose if the router itself was trying to resolve something, not for the clients themselves trying to resolve something.

Something to consider now that Apple isn't using AFP for device discovery, so Netatalk isn't going to help with Sonoma and later...

Avahi is complaining with the warning that libnss-mdns is missing, it's trivial to add it in, as the dependencies are already covered by libsss and avahi...

It's a low risk change, and devices/services that use mDNS will be better off - and even Win10/11 benefit here, as they also use mDNS these days for service and host discovery along with their other means.

 

[ColinTaylor]

As far as I remember, people at the time indicated that libnss would only serve a purpose if the router itself was trying to resolve something, not for the clients themselves trying to resolve something.

This is correct. Adding libnss libnss-mdns would be pointless and not solve the problem discussed in this thread or the previous thread.

 

[sfx2000]

This is correct. Adding libnss would be pointless and not solve the problem.

libnss is already present in the build - it's just missing libnss-mdns...

avahi is also present in the build

 

[ColinTaylor]

libnss is already present in the build - it's just missing libnss-mdns...

avahi is also present in the build

Yes, I meant libnss-mdns (I thought that would have been obvious). But adding it would still be pointless IMHO as it would not solve the actual problem being discussed.

 

[thetechhimself]

What OS and hardware are you running? What version of Asus firmware? Did any change recently? Were you using DDNS before?

Ironically, I also have the same router, and multiple Macs, although I personally don't recommend network connected backups due to security concerns, never mind slow speed, I've also had problems with formerly attached Time Machine backups to routers being hit or miss in restore testing. That said, sure, I'll help you hunt down this bug, for fun. I can duplicate this and review both my own client dns caching and conf changes via shell on the router.

 

[sfx2000]

Yes, I meant libnss-mdns (I thought that would have been obvious). But adding it would still be pointless IMHO as it would not solve the actual problem being discussed.

Actually it does - one has to understand how mDNS works for host resolution.

Since the router is up 24/7, it can be the first source for finding hosts...

And, like this, Asus has a half-baked solution as the avahi implementation is complaining about this very thing.

 

[RMerlin]

Actually it does - one has to understand how mDNS works for host resolution.

Since the router is up 24/7, it can be the first source for finding hosts...

And, like this, Asus has a half-baked solution as the avahi implementation is complaining about this very thing.

Your answer didn't explain how the router needs to be able to achieve name resolution when it's a client that is actually trying to resolve a name.

 

[sfx2000]

Your answer didn't explain how the router needs to be able to achieve name resolution when it's a client that is actually trying to resolve a name.

Because every node that is active in a Bonjour/Avahi network is expected to resolve any inquiries...

Asus, as it stands, has a half-implementation - avahi by itself can handle things, but if libnss is present, it defers to it, much like systemd-resolve on desktop platforms.

So the challenge - remove libnss and break a lot of things, or add libnss-mdns as a low risk add-on...

For Apple devices - don't depend on afpd/netatalk for resolution - Apple Silicon doesn't support it for resolution or transport, and this has been deprecated for years now by Apple for all devices/platforms...

Netatalk is still around, mostly for hobby guys that like to run old MacOS classic hardware - either on metal with hardware, or in software with emulation...

Heck - I would be totally ok with removing all Avahi/Netatalk support, and longer term, getting rid of CIFS/SMB - Apple networks will be better for this, and remember, a router is not a NAS...

Mac and iOS device won't care if these things are removed from AsusWRT - actually, they'll run better without it... and that goes for everything from file sharing to AirPrint and AirPlay. And TimeMachine support is way behind the times compared to the current state of the art... even SparseBundles have changed with APFS - HFS+ is still supported for existing bundle flles, but they will break once over a known limit (spares bundles break with over 100 bands in the bundle for most things).

I would keep USB drive support for folks that like Entware and the RMerlin extended activities...

USB for WAN support - by removing SMB/CIFS/AFP support, this frees up space to get better support for WAN devices that use MBIM and/or QMI support

@RMerlin - Eric, feel free to reach out to me directly...

 

[RMerlin]

Library is fairly small, and nssswitch was already configured to use mdns4-minimal (which probably wasn't working due to the absence of the library).

Seems to be working, pinging a LAN client from the router using the .local FQDN is now working. I'm still skeptical it will have any impact on TimeMachine, since all these years it used to work without it.

 

[ColinTaylor]

I have a hunch it may be related to either my VPN settings or my DDNS configuration. I'm not sure how either of those would affect it, but they were the last things I set up yesterday. I just reset the router again and did a minimal configuration of wifi and DNS settings. I've got a backup running now. I'll try setting up DDNS and then VPN after that and try to catch where it breaks.

Are your backups still working now? Did you discover what changes your were making that was causing the problem? Another user reported an apparent conflict with AdGuardHome, were you using that?

 

[sfx2000]

Library is fairly small, and nssswitch was already configured to use mdns4-minimal (which probably wasn't working due to the absence of the library).

Seems to be working, pinging a LAN client from the router using the .local FQDN is now working. I'm still skeptical it will have any impact on TimeMachine, since all these years it used to work without it.

Older versions of TimeMachine used Netatalk (afp) - this provided host resolution for all AppleTalk File Protocol, both as client and host...

Apple has deprecated this for some time, and on Apple Silicon, it does not exist - everything now is thru Bonjour/Avahi, and there, the expectation is that all clients have a minimal set of capability - hence Avahi complaining about the missing lib...