Upgraded from 2GB of RAM to 8GB Doesn't seem to be utilizing all 8GB

[djlax152]

Hi Guys, Like an Idiot I was Learning and experimenting with Freenas and I tested it out on a RAIDZ pool with only 2GB of RAM. Obviously this didn't work very well but I have now installed 8GB of Ram did a few reboots and i noticed some better performance however When i look at my Physical Memory Utilization neither Active, Cache or wired go above 2GB. It does see all 8GB of RAM because in the graph i have consistently had 5.9GB of free RAM that Freenas will not touch even when I am copying over large amounts of files. Almost like there is a setting that needs to be adjusted for it to use all 8GB of RAM. I tried changing the "vfs.zfs.arc_max" from "1024M" to "4000M" as a quick test just to see if it would start using the extra 6GB and my system crashed with an error saying there was not enough vm.kmem_size memory. I tried looking in the Wiki Doc but i couldn't find something that would help me tune my system. I also tried the Autotune setting, rebooting a few times and this didn't seem to work either.

Can anyone help or point me in the right direction? I was thinking of re-flashing my system with the 8GB installed don't know if that helps


My tunables

vm.kmem_size = 1536M
vfs.zfs.arc_max = 1024M
kern.ipc.nmbclusters = 50000

 

[ProtoSD]

I'm going through this EXACT same problem, I also just upgraded to 8GB of RAM with the same problems!

I'm still experimenting, but try increasing your vm.kmem_size, I made mine about a gig less than what my max reported RAM says. So about 6912M and my zfs.arc_max = 6144M.

Also, if you're using 8.04 there's this: http://doc.freenas.org/index.php/Arcstat

I finally just upgraded to 8.04 last night to wake up to the announcement of 8.04-p1, which is why I hadn't upgraded until now!

 

[ProtoSD]

Oh, and if you accidently "bork" your system and it won't boot after you change a setting, I can help with that. I'm planning to do a video tutorial after I get this worked out.

 

[djlax152]

I'm using the Beta 8.2.0. so after you changed these settings do you actually see in your graph that freenas uses more than 2GB? funny thing is I do notice an increase in performance mostly with browsing and copying files but i just don't see it in the physical memory utilization graph. All the cache, active and wired usage stats flat-line at just a hair under 2GB.

 

[ProtoSD]

I'm using the Beta 8.2.0. so after you changed these settings do you actually see in your graph that freenas uses more than 2GB?

Yes, copy a large file of several GB's and you'll see it increase over 2GB, slowly in my case. I was expecting a better scrub time also, but mine was actually worse.

 

[djlax152]

Thanks Protosd, let me know when you find out what it is. I am very curious to see what my freenas is like utilizing the full 8GB.

 

[William Grzybowski]

I dont remember whether 8.2 beta 2 has autotune by default, it might have capped it before the memory upgrade...

Search for vm/zfs settings in System->Tunables, and delete them if any.

 

[djlax152]

The Autotune was not on by default so i turned it on and then deleted the autotune entries under the system. After i did that it put the entries back but changed the values to the following. I think this may work!! Going to test it later when i get home. I preferred to have the autotune do it because i wasn't very sure about changing these values manually. I think it would be a good idea to have the autotune on by default especially for Freenas newcomers like myself.

vm.kmem_size = 4815319168 Comment "Generated by autotune"
vfs.zfs.arc_max = 4815319168 Comment "Generated by autotune"
kern.ipc.nmbclusters = 5000 Comment "Generated by autotune"

thanks Willam ! Cheers!

 

[gman99]

Hi dj can you tell us if this worked?

 

[djlax152]

Hi guys, sorry for the delay This defiantly worked!! :) I haven't quiet used the full 8GB yet but it is for sure using more than 2. I think its because i just don't hammer my Freenas that much I just use it mostly for file sharing. Weird how it uses the utilizes the memory in the screenshot i was copying over a large amount of files, I would have expected the Cache to spike or something but it seems to steadily rise ever so slowly. I'm guessing because it is building its list of frequently used files and storing them in the cache. As far as performance goes this helped A LOT! most of the pauses and slowness are gone when i am browsing through my directories, I still get the occasional freeze up when browsing through my files but i used to get that even when i had a windows file server, I think its probably my switch or something. Thanks again for all the help! If i may make a suggestion I would change the name of the "delete" button in the system tunables to "Regenerate" and turn Autotune on by default.

Cheers!

 

[unholyeyebrows]

Useful thread - thanks!

As someone with an 8Gb server who has wondered over the last few weeks why only 2Gb of RAM has been in use, I've found this thread very useful. Autotune has released all that expensive ECC RAM I spent good money on.

I second the last poster's proposal to rename 'delete' with 'regenerate' as it is confusing to click 'delete' only to see the tunables, well, regenerate!

Nick