How to dropping cached memory after write

[skyyxy]

Hi everybody, I'm using the TrueNAS Core 13.0U3
Xeon E5 v3 10cores
256GB ddr4 memroy
1.93TB U.2 for L2arc
8*10Gb networks (INTEL x520 dual ports)
24* 16TB WD HDDs

The quesion is：When somebody upload huge files like 2-3TB to the server, after that the memory is full and can't empty by itself ontime. Then the other peoples will creazy slow for read, and I have to reboot the server.

So if its possbile to emtpy the memory by write like systemctl parameter in tunable option? Thanks a lot.

 

[sretalla]

One of the benefits to using OpenZFS is that there are a lot of similarities with the Linux version, so maybe some Linux hints are available here:

zfs: flush cache without exporting

For testing I need zfs' cache to be cold. I can flush caching from the pool by removing the cache disks, exporting and importing the pool. This gives the effect I want. But would really like not to

serverfault.com

Obviously you need to find the sysctl equivalents as those methods described apply to ZFS on Linux only.

 

[somethingweird]

truenas 13U4 & only 13U4.

was flushing ARC cache like crazy. (do some research , before attempting the update)

 

[Davvo]

The temporary solution was to set the sysctl tunable vfs.zfs.arc.meta_prune to 0.
But OP is running U3.

 

[somethingweird]

The temporary solution was to set the sysctl tunable vfs.zfs.arc.meta_prune to 0.
But OP is running U3.

My suggestion to OP was to upgrade to U4. and use this interesting "feature"...

 

[Davvo]

OP should upgrade to U6.1 and then experiment with tunables... Keeping in mind that with OpenZFS 2.2 we will have to work the "knob".

OpenZFS 2.2 released! Here we go...!

OpenZFS 2.2 is now a stable release. https://www.phoronix.com/news/OpenZFS-2.2-Released OpenZFS 2.2 was released today. This isn't your boring "run-of-the-mill" release, with some bugfixes here and there. Nope. This is a big one. Even end-users, and hopefully TrueNAS users, will be able to...

www.truenas.com

@winnielinnie is your guy.

 

[skyyxy]

Thanks a lots for all helps, I will try to upgrade version and try them. Huge thanks again!