Your experience with Synology NAS and Time Machine?

Discussion in 'Mac OS X Server, Xserve, and Networking' started by Cubytus, Feb 12, 2016.

  1. Cubytus macrumors 65816

    Mar 2, 2007
    Hello to all community,

    This topic is to know what kind of experience you had with a Synology NAS and it hosting many Time Machine backups, so as to know if I am the only one having a disastrous experience. I aimed to keep all first-line backups in the same place, namely the Synology NAS, so as to avoid the hassle of manually connecting a FireWire drive to the Macs knowing these have well-known issues with external hard drive standby.

    Mine is an up-to-date Syno NAS hosting a TM backup, exactly like explained there. It is cabled with a single LAN cable to a Gigabit switch, no wifi, itself connecting 5 computers, 4 NASes (inc. Syno, but all running some Linux flavor), one IP phone, the switch just relaying what the DHCP server in the modem is telling it to do. Nothing unusual, and this setup works pretty well. Doesn't run any fancy software, just AFP.

    The Syno NAS usually works for weeks at a time without a hitch, but recently, during heavy use (was gobbling up data from one computer, another NAS while undertaking TM backups from two Macs at the same time), it started repeatedly disconnecting itself from all computers, to the point TM backups couldn't complete, and were then declared "corrupted" by one Mac, while the other simply refused to complete verification, let alone do an incremental backup. I managed to restart the backups, but losing all previous ones in the process as they couldn't be repaired. Obviously, I can't be checking the TM backups every day, can I?

    According to Synology's tech service, my network is unstable and may well have caused the corruption. They ignored the fact that this is probably a bad assumption as the IP phone has not seen a single glitch like it should if the LAN was really unstable, plus the fact no other server on the network posed any issue even with sustained transfers. Their so-called "solution" is to attempt a direct connection to a Mac completely insulated from the Internet (and therefore, unusable), and see if the problem reappears. The problems are, first, this defeat the very purpose of a NAS, second, even with a normal configuration, it takes week to appear - but when it happens, it's not recoverable. I don't know how to reproduce the issue exactly, and at the same time, having to manually switch on a regular external HDD on each machine defeats the whole pupose of having a centralized (and expensive!) storage device.

    A long post leading me to some questions:
    1- Is Time Machine on a NAS prone to issues so severe they result in losing all backups?
    2- Is Synology's NAS box too "sensitive" on a busy LAN? Do something the other NASes don't?
    3- Is Time Machine inherently intolerant to problems that can happen on a LAN such as lost/late packets?
    4- What other protocol would allow versioned backups on the LAN and "repair" itself in case of problems? Teh good ol rsync? Other, non-proprietary ones?
    5- Should I try to make the Syno crash and capture what's going on with, say, Wireshark, although I don't know what I would be looking for?

    - What is your experience with Synology NASes and Macs, overall? I feel ripped-off at the moment, but considering their overall good reputation, maybe it's just a case of "holding it wrong" ;)
  2. dgbarar macrumors 6502


    Feb 27, 2014
    Fountain Hills, AZ
    Hi Cubytus,

    What is unstable is Time Machine as it is not very fault tolerant.

    I had a similar issue as you. Not with a NAS, but with a Western Digital Duo hard connected to a Mac Mini running OS X Server. I would make initial Time Machine back-ups of my MacBooks hard wired to the network. After that, all Time Machine back-ups were performed over WiFi using ASUS RT-AC68U.

    It might work several days, but invariably the Time Machine back-up would become corrupted and I would have to start over. After about 4 weeks I gave up on the concept of using wireless Time Machine back-ups--just too painful.

    Now I back-up my important files wirelessly with ChromoSync daily over the WiFi network. I also back-up the MacBooks with Time about once/week but only with a hard drive connected to the computer.

    Lesson learned. If you are expecting to perform Time Machine back-ups over a wireless network you are expecting to much from this software.


    Donald Barar
  3. Scary Spice macrumors regular

    Scary Spice

    Jul 31, 2015
    British Columbia

    I have always used apple airport or time capsule hardware for Time Machine, (with built in and external USB drives) and always back up wirelessly. I have never had any reliability issues with Time Machine... (I have used it since it debuted years ago).

    Although the interfaces are dumbed down, I find apple's wireless hardware fast and reliable and the most trouble free with OS X.
  4. sandcastle macrumors newbie

    Nov 21, 2014
    I have a DS1812+, backing up an iMac, MBA and Mac Mini. The mini runs OSX Server, and Plex server. There are 2 iPhones and 4 iPads on the network, plus another 2 work laptops.

    Yes, every now and then TimeMachine dies / corrupts and starts over. That's every few months though (or less often) and usually on the iMac that has around 2TB or data, the other devices are very stable. The iMac is wired, so is the mini, but the MBA is wireless.

    I've put it down to TimeMachine instability over a network - I've had friends / family with TimeCapsules and had just as many or more troubles. Given it's only backup, I can handle it, although of course I wish it didn't happen.

    I also backup using CrashPlan. You don't have to subscribe to backup to a NAS drive. That hasn't ever failed / corrupted. Every now and then it has to re-verify (by design?), but just keeps on ticking. Much slower, and eats RAM - think I've needed to increase it's allocation from the standard 512 to at least 1.5GB for the 2TB iMac. In fact I have several friends pointing to my mini server and NAS for their remote backup solution - not a glitch in the years I've had it.

    For what it's worth - CrashPlan has been so stable I pay for the cloud storage and have over 7TB backed up to it. Still use TimeMachine locally as a restore would be much faster, and it does fully bootable backups.

    CrashPlan is really a "house burns down" kind of a last resort solution. Suppose it also means I don't stress so much when TimeMachine has to restart from scratch as I'm still not exposed.

  5. seismick macrumors member

    Oct 14, 2013
    There are many reports on this forum of corrupted time machine backups when backing up to a NAS. My experience has been similar. I used to use a Synology DS413 as a Time Machine target, but it would only work for months at a time before starting over. When backing up to a 4th gen Time Capsule (which I did for 3 years) and to a headless Mac mini running OS X Server (over both wifi and ethernet), the corruption issue has not come up a single time. For Time Machine over a LAN, I'd stick to one of the officially supported methods - Time Capsule, OS X Server, or an external HDD connected to the latest-generation AirPort Extreme (but not prior editions).
  6. Cubytus, Feb 14, 2016
    Last edited: Feb 14, 2016

    Cubytus thread starter macrumors 65816

    Mar 2, 2007
    I do have another line of backup: iDrive, which replaced a chronically-failing SpiderOak, while even local HDD-based TM backup failed due to drive failure. Needless to say I am obsessed about reliability, but somehow never encountered true peace of mind that would have come with fully automated, reliable backups that wouldn't require any manual intervention. Even TM on a local drive requires user intervention because of this annoying bug with firewire where external drives would freeze the entire computer if allowed to sleep while plugged in.

    I found this topic, where some answers explain that basically no NAS manufacturer ever implemented a fully-compatible AFP protocol for Time Machine, leading to instabilities either during backup or when trying to restore. Worse, these corruptions appear randomly, meaning there's no way to prevent them, and Time Machine still does a pretty bad job repairing itself.

    EDIT: Even an older AFP implementation would be an interesting hypothesis, I found this Wikipedia page, though unsourced, saying that Synology's OS is supposed to use AFP version 3.1 (introduced in 10.2), while Apple's own reference requires a networked Time Machine to run 10.5.6 at a minimum (AFP versions 3.2+ or 3.3 according to WP's page).

    If I believe all this info to be correct, would the outdated version of AFP in Synology's OS be one possible source for these problems?

    Naively I expected a $800+ fully equipped NAS renowned for its quality software (!) to be more reliable than a single backup drive provided it doesn't rely upon some flaky, half-reverse-engineered protocol.

    @sandcastle I don't get it, TM is not supposed to make bootable backups at all AFAIK? SuperDuper or CCC would, though.

    Since SuperDuper is just a fancy wrapper around rsync, does it means that rsync would allow versioning just like TM does? Why wouldn't Apple use the protocol, then? Or would rsync simply be a decent, albeit less user-friendly, replacement for TM on a NAS?
  7. McCrab macrumors newbie

    Feb 11, 2006
    Was running a Synology DS 1512 for about 4 years and backing up 4 MBP's, an iMac and a MacMini Server, and running three Apple TV's, 4 iPads, 2 iPhones on the network - the mobile devices on Apple based WIFI (the latest Airport Extremes) and the computers on Gigabit Ethernet using a NetGear switch. All cabling is Cat-6.

    The Synology was reliable for the entire period and I recently (October last year) upgraded it to a DS 1815+ - basically started to run out of storage on the 1512 (TM backups, huge Media library, and photo library and other files). TM has also been reliable during the same period, but I don't rely on it exclusively - also have a separate backup strategy for critical data, like the photo library. I did spec out the Synology with Enterprise class Hitachi drives (or whatever they call them now) - they are bombproof and can give them an unconditional recommendation
  8. Shamgar macrumors regular

    Jun 28, 2015
    I used to have reliability issues with Time Machine backing up to a Time Capsule, but no issues since switching over to a DS415+. Unfortunately, while Time Machine is very user friendly, it sometimes just breaks.
  9. sandcastle macrumors newbie

    Nov 21, 2014
    Sorry - bit loose with my language. TimeMachine means you can "restore from TimeMachine" a new / clean Mac and get back to a running system exactly like it was. That's what I mean (agreed, that's not a bootable backup like CCC etc.). Crash plan backs up all your files, but there's no native integration to make a brand new mac just like the old one - you'd probably have to mess around with software licenses, settings, etc. etc. Still would ensure all really important things like family photos etc. are recovered, but not "back up and running just like you were a few hours later" like TimeMachine (that I know of at least).

    I didn't mean to sound too down on Synology and TimeMachine. Like I said, I had just as much trouble with TimeCapsules and TimeMachine, and 2 out of three machines in the house (including one wireless one) have backed up perfectly for many years without a corrupted / please start over coming from the TimeMachine service. The iMac has only thrown that error a few times in many years of use, but again, "native Apple all the way" TimeMachine threw just as many errors in my experience.

    I've run successful TimeMachine restores from Synology, including for a MacMini running Server, without a hitch. The Synology has also survived at least 2 (I think three) hard drive failures / rebuilds without skipping a beat (as in continuing to serve up content / act as a TimeMachine location for multiple machines while rebuilding).

    Good luck with whatever you do - but as many others will probably say, I wouldn't ever trust a single backup service / product / process, especially one that remains in the same building as the devices you are backing up!
  10. NotTheOne macrumors newbie

    Mar 19, 2014
    Smiths, Bermuda
    Just as a quick note, I know you asked about Sinology but also I have been using TimeMachine reliably on a QNAP for many months. As always the details are in the software, check the version of afpd that your NAS is running and what version(s) of afp it supports, I believe a minimum of 3.2 is needed for Yosemite and El Capitan.

    Run afp -v from the console:

    afpd 3.0.5 - Apple Filing Protocol (AFP) daemon of Netatalk

    This program is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free Software
    Foundation; either version 2 of the License, or (at your option) any later
    version. Please see the file COPYING for further information and details.

    afpd has been compiled with support for these features:

    AFP versions: 2.2 3.0 3.1 3.2 3.3
    CNID backends: cdb dbd last tdb
    afp.conf: /usr/local/etc/afp.conf
    extmap.conf: /usr/local/etc/extmap.conf
    state directory: /var/netatalk/
    afp_signature.conf: /var/netatalk/afp_signature.conf
    afp_voluuid.conf: /var/netatalk/afp_voluuid.conf
    UAM search path: /usr/local/etc/netatalk/uams//
    Server messages path: /var/netatalk/msg/​
  11. Cubytus thread starter macrumors 65816

    Mar 2, 2007
    Hitachi drives also powering this unit here, desktop-NAS units since I couldn't find the enterprise-grade drives Backblaze measured as the most reliable.

    Yours is an example of the unfathomable mysteries of computerized devices: I have less stuff than you, the remainder being rather similar (Though I can't spend $2k or $3k on a loaded NAS - not even sure it would make a difference anyway), usually less= less parts to break, yet more problems. Never lost significant amounts of data thanks to onsite and offsite backups, but many times went through unplanned hours of repairs only to give up when I ran out of ideas.

    Wow, I don't get that one. Less reliability even with Apple's own hardware. Toss a coin, and yoiu won't get any better results.

    And of course TM is user-friendly while it works, but I assume this user-friendliness doesn't come without some great complexity underneath.

    It's actually so complex that it can't easily be repaired, even Apple doesn't have specific tools to repair Time Machine, and if there ¡s no lost data, will simply tell you to erase everything and start all over again.

    As to why I don't have a Time Capsule, first I need more control over my router than Apple provides, second I find it too expensive for what is essentially a glorified router (though less than an Asus anyway!), and third, on paper at least, Synology or other third-party NASes support more protocols than TC, and I run all three major platforms on a regular basis.

    This was yet another concern of mine: lack of user-friendliness of other alternatives ways to have regular, versioned backups:
    From Synology's email:

    "If a wireless connection is preferred then consider using a different backup solution instead of Time Machine."
    Even they admit TM is not stable on their hardware. The question would be: which solution would provide versioned backups and easy recovery?

    On the side track, I was looking for Windows-based versioned backup software that would give something similar to TM: plain files backed up and time stamped, without having to register for any account. or install any software beforehand. Not found so far.

    Not that I would either, but I'd rather avoid the nasty surprise of having to eat up hundreds of GB restarting a new backup, having to deal with blocks of now-useless data bundles because they're unrepairable wither by Disk Utility or Disk Warrior, or having to download tens of GBs of data over a capped connection that's likely to be slow anyway.

    As for the AFP version, I got:
    Synology> afpd -v
    afpd 3.1.1 - Apple Filing Protocol (AFP) daemon of Netatalk
    This program is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free Software
    Foundation; either version 2 of the License, or (at your option) any later
    version. Please see the file COPYING for further information and details.
    afpd has been compiled with support for these features:
              AFP versions:    2.2 3.0 3.1 3.2 3.3 3.4
             CNID backends:    dbd last tdb
                  afp.conf:    /etc/afp.conf
               extmap.conf:    /etc/extmap.conf
           state directory:    /etc/netatalk/
        afp_signature.conf:    /etc/netatalk/afp_signature.conf
          afp_voluuid.conf:    /etc/netatalk/afp_voluuid.conf
           UAM search path:    /lib//
      Server messages path:    /etc/netatalk/msg/
  12. jgreenb2 macrumors newbie


    Mar 24, 2017
    @Cubytus: as of DSM 6.1 there's a very nice workaround for TimeMachine backups on Synology. Even with SMB as the transport I have occasionally experienced the dreaded 'verification error' and had to discard my history and start a new backup. Very frustrating. This happened on a TimeCapsule also but it occurs much more frequently on Synology over AFP and I have had it happen once over SMB.

    But if you are using the Btrfs file system you can use the snapshot feature to quickly recover. Snapshots are called 'replications' on DSM and there is a Replication Manager package that controls how often shared folder snapshots are taken. The snapshots are created instantly, require very little disk space and can be restored in seconds. This works best under DSM 6.1 where you can devote separate shared folders to each TimeMachine user.

    Simply launch the Replication Manager and arrange for a snapshot of each TimeMachine directory to be taken every 12 hours. Now, if you get a verification error, simply use the Replication Manager to restore the corrupted directory using a snapshot. The process takes only seconds. At most you will lose 24 hours of TM history.

    It would be better if these errors didn't occur but there's something about the structure of Apple's sparsebundle images that really stresses most filesharing implementations. Apple's version of AFP seems the most reliable but, as I indicated, even a TimeCapsule can fail.

    Good luck!

  13. Cubytus thread starter macrumors 65816

    Mar 2, 2007
    @jgreenb2 Alas, I went with what I knew at the time, meaning ext4. I assumed at the time it would be easier to rebuild the RAID1 volume on Linux should the NAS fail, but maybe btrfs is also Linux-compatible, I don't know.

    That means a conversion to Btrfs isn't very practical, unless I dump all the already backed-up files. From what I could read, tranferring back and forth such a large amount of data is painfully slow.

    So using Btfrs on a TM folder is equivalent to doing "snapshots-of-snapshots"? Should a TM backup become corrupted, is a Btrfs snapshot able to "magically" recover corrupted files, and still keep the full TM history ?

    Looks too good to be true! What are the issues of using Btrfs instead of ext4?
  14. jgreenb2 macrumors newbie


    Mar 24, 2017
    Honestly, I haven't seen any issues with Btrfs. It is sort of a "snapshot of snapshots" but the underlying way it's done by TM and Btrfs couldn't be more different. But it doesn't really matter. No matter how complex the TM sparsebundle is, a Btrfs snapshot is an exact copy. And yes, you really can overwrite a corrupt backup with a snapshot in a couple of seconds.

  15. Cubytus, Mar 25, 2017
    Last edited: Mar 25, 2017

    Cubytus thread starter macrumors 65816

    Mar 2, 2007
    Please excuse my ignorance. There was a Wiki page on Btrfs, and it has been considered stable on Linux since 2014. On a regular Linux box, there's an option to perform in-place conversion of ext4 to Btrfs, but not in Synology's version. And Synology's page doesn't list the DS215+ as a compatible model :-/

    Other users (on Reddit, FWIW) opted for ext4 since its flaws are already "well known", making a potential repair easier.

    Synology's knowledge base says Btrfs allows "file self-healing", how does this differ from regular filesystem snaspshots?

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