Scanning (almost) stops - (Apple Macbook to NAS)

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Posts: 3
Joined: 11 Oct 2018

Hc1

The setup
The system involves a Windows 10 PC, MacBook and a Synology NAS. All running the latest updates (e.g. Mojave), connected via Gigabit cable.
Performance of FreeFileSync on Windows is perfect, circa 320k files are scanned on the NAS at several 1000 files per second. Transfer of files runs at about 450Mbit/s.

The problem
On the Apple Macbook everything starts and runs with a similar performance to the Windows machine. However after circa 52k files, the scanning ' pauses' sometimes for several seconds then runs in stages usually at about 30 or 30 files a second for several minutes. But it works, the scanning is just incredibly slow.

The NAS is setup for SMB, I heard that Apple deprecated AFP, so I turned it off in the NAS. Transfer speed to the NAS from with both computers is always about 450 MBit/s.

Question
Any idea what FreeFile Sync is doing on the Macbook that causes it to slow down so much ?
Any idea what I can do to change the settings either on the Macbook or NAS ?
All ideas and help is much appreciated.
Posts: 21
Joined: 5 Oct 2018

jmsxl

I have the same problem with a similar setup; Windows 10 and Macbook Pro each mirroring to a Synology NAS. Been this way since the 9.x releases. FFS on Windows 10 is blazingly fast; FFS on the Macbook runs in fits and starts. The first 82,000 files are searched in 2-3 seconds and then I get pauses of up to 45-90 seconds. The backup eventually completes but it is MUCH slower than things were in the early? 9.x release timeframe. NAS is mounted on the Macbook using AFP but I tried SMB and it has the same issue.
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Zenju

If the performance issue is related to FreeFileSync, with which version did these delays start to occur?
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Joined: 11 Oct 2018

Hc1

To be more specific, This is about FFS on a Mac and syncing with data on a Synology NAS. The windows setup works fine e.g. 330k files are scanned in circa 65 seconds.
However All Mac versions of FFS I used showed an issue of scanning rapidly (with Windows like speed) up to circa 52k files, then it would dramatically slow down and continue, completing its cycle of circa 80k files in about 6 minutes.
I tried everything I could think of e.g. turning of digital signing etc. that restored file transfer speeds to being comparable to Windows speeds e.g. 450Mbit/s, but scanning (not transfer) was still an issue.
On using FFS 10.4, this slow down got worse, the scanning would simply stop, sometimes for several seconds at a time, and always at different files. It would then continue for up 20 minutes or more. I had to stop using FFS then for the MAC and resorted to Synology's Drive,that works fine, but then the architecture is different - its a client -server rather a external HDD model. Hope this helps.
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Joined: 5 Oct 2018

jmsxl

I got an unexpected result experimenting with FFS v9.0. With that version, the scanning operation progresses at a steady, nearly linear rate throughout the scan until it finishes. With v10.5 (and as I recall all 10.x and many 9.x versions,) the scanning jumps to ~80,000 files processed in the first few seconds and then it displays dramatically smaller increments in progress, sometimes 50-100 files / second and sometimes halting displayed progress for 45-90 seconds before showing an update.

But the interesting thing is that the total scan time is virtually the same with v9.0 and v10.5 FFS. So while the rate of scan updates is quite different in the two versions, I now conclude that the overall performance has not degraded. In my view it is the change in displayed scan progress that gives the perception of a slower speed in v10.x. I now consider this a non-issue.
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Joined: 11 Oct 2018

Hc1

Indeed I also noticed this very erratic display speed, if that were the only case it would indeed be a non issue, however in the problem reported on this thread the issue was a much longer scanning rate, by about an order of magnitude (x10) compared to previous versions and especially compare to a windows FFS system.
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Zenju

@jmsxl: Your observation is correct! The apparent "hangs" are in fact situations where FFS is busy traversing lots of directories one after another. The corresponding "analysis steps" that update the stats as shown on the GUI are queued to the back of the workload. This then leads to a sudden "surge" of new items that are found, when in reality FFS is just analyzing the data it has "buffered".

This behavior isn't deliberate, but an artifact of the new FFS 10 multithreaded folder traversal which divides the work into multiple steps, simplified: 1. listing of folder items 2. analysis of these items (file, folder, symlink) + update of the UI stats.
A naive folder traversal automatically does some interleaving (e.g. while listing each folder item, it is directly analyzed before continuing with the next). With FFS's task-based architecture this interleaving doesn't happen naturally, *but* it can be introduced without loss of performance by a careful sequencing when inserting work items to the queue. I have implemented this for the next version so that stats progress gradually rather than in bursts.

https://www.mediafire.com/file/spcb9sum619e6i1/FreeFileSync_10.6_beta_macOS.zip
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jmsxl

@HC1: Understood; thanks!