EDIT I FOUND FIX / RESOLVED: the issue was that i was not using the proper "size" / multiple , ie this works:
sysctl vfs.zfs.arc_max=8226053120
however i cant figure out a number below this 8gb that will take (keeps saying invalid arg) any ideas? id like to have no or very little arc set for my benchmarking.
it does seem like the you have to use multiples of 1024 (ie your number must be evenly divisible by 1024) , please correct me if im wrong, but i still cant get below the 8g above
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to be clear, i would never mess with these settings on my final system. however for the past week (and a few more weeks), im just testing various disk layouts and configs with FN.
Im trying to benchmark different disk layouts, however as i have 128g of memory, almost all of my tests results are from cache.
Im trying to set my arc to 4gb, i cant find info in the fourms on how to do this via the CLI (which i read will make the change instantly).
what am i doing wrong (i keep getting invalid arg)? Or is there a better way i should be disabling cache for my benchmarking (other than pulling out ram, as i have 32gb sticks) thanks
root@freenas:~ # sysctl vfs.zfs.arc_max=4808424960
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=4808424960: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=65808424960
vfs.zfs.arc_max: 65808424960 -> 65808424960
root@freenas:~ # sysctl vfs.zfs.arc_max=6808424960
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=6808424960: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=4294967296
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=4294967296: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=4G
sysctl: invalid uint64_t '4G'
root@freenas:~ # sysctl vfs.zfs.arc_max="4294967296"
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=4294967296: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=4096M
sysctl: invalid uint64_t '4096M'
EDIT: AutoTune is disabled (and has never been turned on) , (the reason im not using tunables in the GUI is im trying to avoid needing to reboot each time)
sysctl vfs.zfs.arc_max=8226053120
however i cant figure out a number below this 8gb that will take (keeps saying invalid arg) any ideas? id like to have no or very little arc set for my benchmarking.
it does seem like the you have to use multiples of 1024 (ie your number must be evenly divisible by 1024) , please correct me if im wrong, but i still cant get below the 8g above
------
to be clear, i would never mess with these settings on my final system. however for the past week (and a few more weeks), im just testing various disk layouts and configs with FN.
Im trying to benchmark different disk layouts, however as i have 128g of memory, almost all of my tests results are from cache.
Im trying to set my arc to 4gb, i cant find info in the fourms on how to do this via the CLI (which i read will make the change instantly).
what am i doing wrong (i keep getting invalid arg)? Or is there a better way i should be disabling cache for my benchmarking (other than pulling out ram, as i have 32gb sticks) thanks
root@freenas:~ # sysctl vfs.zfs.arc_max=4808424960
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=4808424960: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=65808424960
vfs.zfs.arc_max: 65808424960 -> 65808424960
root@freenas:~ # sysctl vfs.zfs.arc_max=6808424960
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=6808424960: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=4294967296
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=4294967296: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=4G
sysctl: invalid uint64_t '4G'
root@freenas:~ # sysctl vfs.zfs.arc_max="4294967296"
vfs.zfs.arc_max: 65808424960
sysctl: vfs.zfs.arc_max=4294967296: Invalid argument
root@freenas:~ # sysctl vfs.zfs.arc_max=4096M
sysctl: invalid uint64_t '4096M'
EDIT: AutoTune is disabled (and has never been turned on) , (the reason im not using tunables in the GUI is im trying to avoid needing to reboot each time)
Last edited: