Doi have enough Memory?

[gwaitsi]

My memory stats show

0.5GiB free
ZFS Cache 10.9GiB
Services 4.4GiB

does ZFS need that much cache? if i add services, will it take ram from the cache and free ?

 

[Fredda]

That is normal, over the time all of the free memory will be used for ZFS cache.
Why should it left free, if can be used for something useful.

Linux pretty much does the same:

Code:

~# free -m
              total        used        free      shared  buff/cache   available
Mem:          63001        9121       11934         373       41944       52993
Swap:         31996           0       31996

 

[gwaitsi]

presumably, ZFS requires some minimum amount of cache to be effective. At what sort of point, should i be looking at more memory for example

 

[sretalla]

Look at your ARC stats, if your hit rate is low, you could benefit from more RAM.

arc_summary.py

 

[gwaitsi]

Look at your ARC stats, if your hit rate is low, you could benefit from more RAM.

arc_summary.py

what is the command i would have to run from the shell pls

 

[Fredda]

The command is exactly what @sretalla wrote.

You can also view the Arc Hit Ratio via the GUI: Reporting->ZFS
(But the command offers much more info)

 

[gwaitsi]

cache hit 94.3%, miss 5.7%, actual hit 94% - so its all pretty good. no

 

[sretalla]

cache hit 94.3%, miss 5.7%, actual hit 94% - so its all pretty good

Obviously a small margin for improvement, but generally, your use seems to land most of what you're seeking in RAM.

If you run more services/jails/VMs, you might want to review the numbers again and see if the reduced ARC is having a big impact.