Mac OS // SMB // Zfs ARC metadata collapse

[mickeytankbank]

I have a similar problem where SMB volumes just hard dismount from OSX when running Backup apps like carbon copy cloner or Chronoync on large folders (10k+ items). I noticed my ARC request metadata stats jump to 60m when this happens. Can someone explain to me what kind of unit 60m is? Bits? Bytes? or does it mean "million" as in 60M? I assume "m" would mean "milli" hence my confusion. Thanks! Not sure why scanning a folder with 10k items creates an ARC hit of "60m" (whatever unit that is). (the other thread with screen shot https://www.truenas.com/community/t...ismount-under-osx-ventura.113610/#post-786158

Sometimes just opening such a folder on OSX dismounts the volume after a few seconds.

It's definitely a bug in trueNAS, not macOS, but you can work around it with CCC if you set CCC to use the legacy file copier under advanced / file copier concurrency.

 

[John45622]

It's definitely a bug in trueNAS, not macOS, but you can work around it with CCC if you set CCC to use the legacy file copier under advanced / file copier concurrency.

What does that do or what does it do differently? Couldn't find any info in the CCC docs.

 

[ChrisRJ]

Irrespective of other aspects it is hardly ever a good idea to have 10k+ files in a single folder.

 

[mickeytankbank]

What does that do or what does it do differently? Couldn't find any info in the CCC docs.

They never really say exactly, just that they completely rebuilt the file copier for version 6, and that it's now multithreaded. I think maybe it's the multithreaded part thats overloading TrueNAS.

 

[John45622]

You might want to send that message to AVID and other professional media software makers and explain to them that having 10k files in a folder is OK on MacOS but for TrueNAS they should change their programs so that only 1000 files ever exist in a ProTools project (which dopesn't even cover the files of your last short film shoot) if you want to share them over TrueNAS. ;-)
The last blog post for Dragonfish boasts the handling of "billions of files" on TrueNAS.

 

[Davvo]

I wouldn't be so sure in identifying TN (which version?) as the culprit.
SMB is no work of art, and Apple is no Holy Grail.
If you believe to be a TN bug, please file a Bug Report. Opening your own thread might help as well... besides, the blog post of Dragonfish refers to the last version of SCALE, this thread is in the CORE section: the two products are substantially different.

 

[John45622]

I wouldn't be so sure in identifying TN (which version?) as the culprit.
SMB is no work of art, and Apple is no Holy Grail.
If you believe to be a TN bug, please file a Bug Report. Opening your own thread might help as well... besides, the blog post of Dragonfish refers to the last version of SCALE, this thread is in the CORE section: the two products are substantially different.

Not entirely sure who you're referring to when you say "you" but the dismounts with excessive metadata request I mentioned totally referred to Core. It was quite on topic. Then someone said it's not a bug just wrong usage ("don't put 10k files into one folder").
But for what it's worth: Since I've posted I have since moved to Scale and the dismounts went away. My mac hasn't changed and the OS is still also the same (Ventura) and yet no more dismounts. The only thing hat changed is TN. I was just curious how the person who said that you can work around the issue is doing it. And also:TN for years was saying they have countless installation in media houses. No one would be using TN in these places if having 10k files in a folder is a user error in principle.
But for me personally, the case is closed anyway. Bye for now....

 

[John45622]

Irrespective of other aspects it is hardly ever a good idea to have 10k+ files in a single folder.

This official TN doc says that

"Starting in Dragonfish 24.04 and later, the meta-data performance of directory listings over SMB is greatly improved. Depending on your SMB client, it is possible to support a single directory with anywhere from 100,000 to 1,000,000 files on flash systems with decent load times."

So I guess even 10k files is exponentially under what's possible. (on Scale that is and if you can live with the load times, but in principle 10k+ files in folders are no problem at all)

But now that Core is going away it's probably not worth investigating into it any longer.

SMB Directory List Times

Performance data tables when listing large files counts over SMB.

www.truenas.com

 

[Davvo]

But now that Core is going away it's probably not worth investigating into it any longer.

CORE is not yet going away dude.