Hi, I want to increase my ZFS ARC size.

 

System had very little RAM when it was installed, so ZFS ARC has been 12GB for quite some time (Year+)

System now has 256GB RAM, but ignores the higher ZFS ARC value..

- Even though flash "/boot/config/modprobe.d/zfs.conf" (without me changing anything? - changed by later upgrades?) says:
# limetech - Default ARC size is MemTotal/8 (in bytes)
options zfs zfs_arc_max=33805315072

 

- I also tried to create the same in /config/....  as by documentation.

- I replaced the OLD tired slow usb drive

- So brand new fast USB, fresh version of Unraid + same config files + transfered license

It does NOT change, but stays at 12GB.

Not exactly a Linux/Unix expert, but have worked with Solaris ZFS storage for years:

- ZFS pools are fine.

- Can it be an "initramfs" issue?

- Or ? ? ?

 

Please, give some "bright" ideas 🙂 

 

Thanks, Dannie

 

Edited July 9, 20241 yr by Virtualizer
Changed "Not exactly a "Linux" expert, to more correct "Linux/Unix"

You just need to create the zfs.conf file and reboot, example:

 

root@Tower7:~# cat /boot/config/modprobe.d/zfs.conf
options zfs zfs_arc_max=125737758720

 

Thanks JorgeB,

 

Sorry if may explanation was not fully understandable.

 

The ZFS ARC is currently 12GB

The File /boot/config/modprobe.d/zfs.conf - says "33805315072" approx 32GB

 

Known issues (lines ending with cr/newline) - NO, I did NOT modify the file, it must have been changed by one of many updates/upgrades (over several years).

Yes it has been rebooted several times.

 

Thats why I am frustrated 😞

Post the exact output of the file, like I did above

I did in the original post:

 

'# limetech - Default ARC size is MemTotal/8 (in bytes)
options zfs zfs_arc_max=33805315072

Ans the output of:

 

cat /proc/spl/kstat/zfs/arcstats | grep c_max

 

root@NNIE-UNR1:~# cat /proc/spl/kstat/zfs/arcstats | grep c_max
c_max                           4    12884901888

 

Something must be wrong with the file, or the flash drive, copy this file on top of that one and reboot:

 

zfs.conf

 

 

Thanks,

 

I did replace the USB with a brand new, that did not change anything (other than booting a little faster).

Besides running the home stuff, it is also running my wife's company, so reboots are only possible during my service windows in the weekends.

 

Thanks for your quick response.

I will try to replace, rename and delete the file, to see if it is a file issue.

 

Have a nice week, I will get back during the weekend.

 

Regards, Dannie