RAM is barely being used!

[smartypantsuk]

Hi,

I have recently moved from Scale to Core (rightly or wrongly), and since moving the RAM usage has gone weird.
On scale, most of the RAM was always in use, as I would expect, but on Core it's hardly used at all.
No tunables or anything like that.

ZFS Mirror: 1.47 TiB (28%) Used | 3.85 TiB Free
No VM's, Plugins or anything else installed.
I have two SMB shares.
Tried two installs with the same result.

How can I fix this?
Thanks

 

[Ericloewe]

How long has the system been up and how much use has it seen? Nothing's going to end up in ARC if nothing gets read.

 

[smartypantsuk]

How long has the system been up and how much use has it seen? Nothing's going to end up in ARC if nothing gets read.

Admittedly the system has only been up a week, and not seen a massive amount of use...
although I did write around 900GB over the last day as I was moving some of my media collection to the NAS.

I've only just found the arc graphs under reporting...
this is what they say for the period I moved the 900GB.

arc size:

Key	Min	Mean	Max
Arc :	174.74 MiB	4.38 GiB	12.73 GiB
L2 :	0	0	0

hit rate:

Key	Min	Mean	Max
Arc :	97.15	99.88	100
L2 :	null	null	null

so maybe that's okay? I have no clue as I'm very knew to TrueNAS in general.
All I remember was that the SCALE setup was always using up most of the RAM i threw at it and that wasn't operational very long.

Thanks

 

[Apollo]

You can have a look at the graphs under "Reporting" => "ZFS" section.
You can zoom out to get a larger timeframe.
Under "ARC Size" and "ARC Hit Ratio", you should be able to see if the memory is being used and possibly cleared/flushed.
Depending on the type and amount of data, 16GB may not be enough and you would see significant drop in the "ARC size" and "ARC Hit Ratio".
Doing replication will consume RAM and is more likely to flush the memory doing so.

 

[winnielinnie]

although I did write around 900GB over the last day as I was moving some of my media collection to the NAS.

Writes, not reads.

As you read data from the storage pools, your ARC will grow.