FreeNAS -Error Not Enough Memory

[erez]

Dear Members,

To begin, I am runnig FreeNAS-11.3-U2 on a certified server purchased from IX Systems with 250GB of memory (full specs below if interested). I currently have 2x Windows Server 2016 and 2x Ubuntu Server 18.04 VMs running as per below:

-Win Serv 1: Memory 80G
-Win Serv 2: Memory 16G
-Ubuntu Serv 1: Memory 4G
-Ubuntu Serv 2: Memory 10G

Whilst Trying to spin up another VM with memory allocation 16G, I am getting an "Error not enough memory" where i can select to over commit. However on the dashboard I am seeing Service Memory 100G, ZFS Cache 53G, and Free Memory 95G

So my qestion is why am I seeing the over commit memory prompt?

If anyone's encountered this before and can offer some advise it will be greatly appreciated.

Thanks in advance.


Full Server Specs:
1U Mercury Dual Xeon Rackmount Server - 4 Bay Hot-Swap SAS3/SATA3 Drive Bay,
750W Redundant Power Supply,
Dual Socket Xeon Motherboard (Intel C602 Chipset) - 16 DIMM Slots (1TB Max Memory) -
8 x SATA2, 2 x SATA3 - Intel i350 Dual Port LAN, (7) PCI-E Expansion Slots + IPMI
Dedicated LAN
2xIntel Cascade Lake Ten Core Xeon 4210 SILVER - 2.2 Ghz 13.75MB cache (85W)
8x32GB DDR4 2933Mhz 23400 ECC/REG (256GB Total)
2x32GB MLC 6Gb/s Internal SATA Boot Device (Mirrored)
4xHGST 6TB Enterprise Nearline SAS 12Gb/s 7200RPM 256MB 4KN TCG

 

[Mark Levitt]

I've noticed the same thing.

 

[Yorick]

Set your vfs.zfs.arc_max tunable. Installed memory minus 4GiB minus memory set aside for VMs. In your case, the value of this tunable would be 126G.

Reboot, and try again, it should then work.

 

[erez]

Thanks Yorick Makes sence. Looking at my arc size currently 35G, is there a reason i shouldent limit vfs.zfs.arc_max to lets say 64G, allowing additional space for future vms?

I had a look at https://wiki.freebsd.org/ZFSTuningGuide but can't find any reason not to?

 

[SweetAndLow]

Thanks Yorick Makes sence. Looking at my arc size currently 35G, is there a reason i shouldent limit vfs.zfs.arc_max to lets say 64G, allowing additional space for future vms?

I had a look at https://wiki.freebsd.org/ZFSTuningGuide but can't find any reason not to?

Your arc just hasn't grown yet. It will eventually max out your ram after you use the system. After a reboot it has to rebuild the cache.

 

[Yorick]

If you want space for future VMs and don’t mind having less for ARC, go for it.

 

[erez]

Thanks All... Gratly appreciate your assistance.
[SOLVED]