how to set up RT TimeMachine server?

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Regular Contributor
Does Time Machine work reliably on ASUS RT-AC3200? Where are complete setup instructions?

I'm running ASUS stock firmware but will switch to Asuswrt-Merlin if that makes TM reliable (and the inactive-disk spindown feature would be a huge plus). Custom-config-files mentions postconf scripts adisk.postconf, afpd.postconf, and avahi-daemon.postconf for Time Machine, but where do I get them?

About disk drive requirements, ASUS tech support said, "any USB 3.0 drive should work and it should spin down when idle."

I formatted a Seagate Backup+ drive for JHFS+ and eventually got it to take a network backup. But then the Mac no longer thinks that drive is available -- just another drive with the same name, so TM has to restart from scratch. And the disk doesn't spin down.

FWIW, the router's log has messages like:
cnid_dbd[1530]: Couldn't load extension -> type/creator mappings file "/usr/etc/extmap.conf"
afpd[1720]: afp_disconnect: trying primary reconnect
afpd[1348]: Reconnect: transfering session to child[1544]
afpd[1348]: Reconnect: killing new session child[1720] after transfer
afpd[1544]: afp_dsi_transfer_session: succesfull primary reconnect
afpd[1720]: afp_disconnect: primary reconnect succeeded
afpd[1544]: AFP logout by <admin>
afpd[1544]: AFP statistics: 69.49 KB read, 308.00 KB written

The router's External USB disk health scanner reports:
/usr/sbin/ eval: line 1: fsck_msdos: not found

** /dev/sda2
** Checking HFS Plus volume.
** Checking Extents Overflow file.
** Checking Catalog file.
** Checking Catalog hierarchy.
** Checking Extended Attributes file.
** Checking volume bitmap.
** Checking volume information.
** The volume sda1 appears to be OK.

but OSX Disk Utility doesn't find any problems when the drive is connected to the Mac.



Regular Contributor
I got it working after these steps. (It's unclear which were needed and what other choices were needed.)
  • Repartition the Seagate drive as ext3 partitions with an msdos partition table using GParted.
    • Actually it froze up part way and wouldn't respond to anything but force-power-off. Retrying got stuck at a different place, so I returned that drive, bought a WD My Book, and formatted that one with ext3 partitions.
  • Ran the router's External USB disk health scanner.
  • Set the Samba name and the HD partition names to short alphanumeric names and turn on "Simpler share naming". (One web article said to avoid special chars.)
  • One partition for Time Machine; one for Samba.
  • [Edit] Install Asuswrt-Merlin 378.54_2.
  • [Edit] Set disk spindown idle time = 120 secs.
  • On Mac, configure Preferences / Energy Saver / Put hard disks to sleep when possible = No. (There's a claim this fixes problems with finding the backup disk. I'm skeptical.) Turn on Time Machine and connect using the router's admin account.
Q. Why does TM on Mac list "two" disks afp://[email protected]_afpovertcp._tcp.local./Backups.backupdb and afp://RT-AC3200-1234.local/Backups.backupdb?
Q. Is it possible to set up a separate TM partition per Mac to back up?
Q. Is it possible to make user accounts work?
Last edited:


Regular Contributor
Q. Is there a fix for log warnings like "afpd[15929]: ad_valid_header_osx("/tmp/mnt/b1/.___var.txt"): not an adouble:eek:sx file"?


New Around Here
Has anyone successfully got Time Machine working? I am getting back_msdos: not found errors on my usb 3 drive.


Regular Contributor
Are you seeing "back_msdos: not found" in the router log, Mac UI, or Mac log? Is that the exact error message? Is there more information in the logs? Is back_msdos the disk name?

* Try searching (all about Time Machine), e.g. "not found" . That yields suggestions, e.g. for "The backup disk is not available."

Also try"time+machine"+"not+found"

Q. Did you do all the setup steps I listed above?

(BTW, I changed disk spindown idle time = 300 secs since a smaller time causes a warning message in the log even though the UI doesn't reveal that minimum.)

* Time Machine on my Mac shows two available disks, as I mentioned above. Hovering over the working one shows the path "afp://[email protected]_afpovertcp._tcp.local./Backups.backupdb", using the router's admin login credentials. Hovering over the other "disk" reveals the path "afp://RT-AC3200-1234.local/Backups.backupdb".

Q. Can you successfully connect to that network disk in the Finder? Once connected, does Time Machine work?

* Also try rebooting the router. In my experience, this does fix some problems. Or even try the long reset rain-dance.


New Around Here
So far my fix was to abandon all drive formats and go with NTFS. I did change the drive spin down idol to 300. I have successfully backed up 750GB and a second Mac of 100gb without a hitch. The drive has not reported any errors at all even after several reboots. All Hourly Backups have been completing on schedule and without error.


New Around Here
I just purchased this router to replace a Netgear R6400. I used to have a Time Capsule but it was crashing daily because of the usage we were subjecting it to. The Netgear had documented issues with Time Machine, and I am/was hoping the RT-AC3200 wouldn't have similar issues either. If I can't fix this, I'm going to start thinking that El Capitan (10.11.3) is the issue.

My current setup is an Asus RT-AC3200 with a WD 3TB drive hooked up to the USB3.0 port. The system successfully completes the first backup, but once it tries to do an incremental hourly backup, I'm prompted with a message saying TM couldn't verify the backup and a new one is needed. Is anyone else seeing this issue?

I will test out your fixes tonight - thanks for sharing. Have you had any success with the latest El Capitan releases? All told, once again very disappointed by an Apple solution - there should be a way to make TM work without having to buy a Time Capsule, which is a mediocre router at best.



Regular Contributor
Have you had any success with the latest El Capitan releases?

On one Mac, yes. But another Mac got the couldn't-verify problem every few months.

I switched from asuswrt-merlin to stock ASUS firmware so I could report the problem to ASUS. Hopefully ASUS tests Time Machine. (RMerlin does not.) Unfortunately, stock ASUS firmware won't spin down the idle disk, and the always spinning sound is annoying. So I set up a Synology NAS with TM and am switching over to that. (Note: To put a disk quota on each Mac's TM, either create a separate volume or create a separate TM user.)

Posts in some forums -- going back many OSX releases -- say TM is reliable only with an attached disk (DAS). Some people speculate that the problem occurs if the Mac goes to sleep while backing up, but that's a questionable hypothesis since it can backup in sleep mode.

  1. Use a Synology NAS. It's supposedly well tested and supported. Will the couldn't-verify problem happen?
  2. Use a Time Capsule just for backup, turning off its router. (This is no sillier than turning off the ASUS router's TM server.)
  3. Use Time Machine with an attached disk.
  4. Use other backup software, such as CrashPlan.


New Around Here
After doing some research...

El Capitan (10.11.x, up to 10.11.4) completely breaks Time Machine support for NAS drives. Do yourself a favor, skip the headache, and buy a copy of CarbonCopyCloner for your household ($39). I've been playing with it all day and not only is the application amazing, but the supporting documentation is phenomenal.



Part of the Furniture
TM has always been pretty much Apple specific for network support - lots of companies have tried to reverse engineer things - and they'll work for a bit, usually until the first 4 weeks go by, and then when the TM client decides to thin the sparsebundle - boom, it goes corrupt...

Small Scale - direct attached storage is best
TimeCapsule is good for 3-5 clients, but as noted by OP, it tends to get overwhelmed by more than 5 clients backing up to a TimeCapsule
Mac OSX Server App - this is the way to go...

Pick up an older Mac, and toss a bunch of drives at it, and run Server.App ($20 USD on the App Store) - a Mac Mini that can run El Cap (OSX 10.11) is $500, and OSX server can do more than just host TimeMachine - it can meet a lot of needs for a small business, and support Mac/Win/Linux...

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