Reasons of poor performance

Status
Not open for further replies.

Recown

Cadet
Joined
Jun 19, 2017
Messages
2
Greetings! I found a little script on this forum, and it shows, that performance of my FreeNas is pretty low... Here is the result

[*]Media files, distributives, libs for dev
[*] 5:15PM up 139 days, 23:52, 1 user, load averages: 0.05, 0.04, 0.05
[*]1023MiB / 74.5GiB (freenas-boot)
[*]18.5TiB / 29TiB (tank)
[*]50.70GiB (MRU: 4.40GiB, MFU: 46.30GiB) / 16.00GiB
[*]Hit ratio -> 28.99% (higher is better)
[*]Prefetch -> 17.65% (higher is better)
[*]Hit MFU:MRU -> 22.08%:39.90% (higher ratio is better)
[*]Hit MRU Ghost -> 79.64% (lower is better)
[*]Hit MFU Ghost -> 14.30% (lower is better)

I cant find any detailed information about what is MRU and MFU Ghost. Just know, that it's some part of MRU and MFU areas of ARC cache.
Am i right, that the main reason is only 16GiB RAM for 18.5TiB storage?
P.S. I am sure, that FreeNas is great! I just want to understand what i am doing wrong...
 

SweetAndLow

Sweet'NASty
Joined
Nov 6, 2013
Messages
6,421
Greetings! I found a little script on this forum, and it shows, that performance of my FreeNas is pretty low... Here is the result

[*]Media files, distributives, libs for dev
[*] 5:15PM up 139 days, 23:52, 1 user, load averages: 0.05, 0.04, 0.05
[*]1023MiB / 74.5GiB (freenas-boot)
[*]18.5TiB / 29TiB (tank)
[*]50.70GiB (MRU: 4.40GiB, MFU: 46.30GiB) / 16.00GiB
[*]Hit ratio -> 28.99% (higher is better)
[*]Prefetch -> 17.65% (higher is better)
[*]Hit MFU:MRU -> 22.08%:39.90% (higher ratio is better)
[*]Hit MRU Ghost -> 79.64% (lower is better)
[*]Hit MFU Ghost -> 14.30% (lower is better)

I cant find any detailed information about what is MRU and MFU Ghost. Just know, that it's some part of MRU and MFU areas of ARC cache.
Am i right, that the main reason is only 16GiB RAM for 18.5TiB storage?
P.S. I am sure, that FreeNas is great! I just want to understand what i am doing wrong...
Huh? Are those numbers bad? Please list what they should be or compare it to a similar system.

Sent from my Nexus 5X using Tapatalk
 

MrToddsFriends

Documentation Browser
Joined
Jan 12, 2015
Messages
1,338

brando56894

Wizard
Joined
Feb 15, 2014
Messages
1,537
MRU: Most Recently Used
MFU: Most Frequently Used

16 GB of RAM is pretty low for 18 TB, you're leaving yourself very little room for an ARC.
 

Ericloewe

Server Wrangler
Moderator
Joined
Feb 15, 2014
Messages
20,194
MRU: Most Recently Used
MFU: Most Frequently Used

16 GB of RAM is pretty low for 18 TB, you're leaving yourself very little room for an ARC.
Huh? It's a very reasonable amount of RAM.
 

SweetAndLow

Sweet'NASty
Joined
Nov 6, 2013
Messages
6,421

SweetAndLow

Sweet'NASty
Joined
Nov 6, 2013
Messages
6,421
Isn't the "rule of thumb" about 1 GB/ TB? I didn't mean "low" as "detrimental", I just meant it doesn't leave a lot of room for an ARC.
Those numbers are just made up and a good guide to go by. Anything after 16GB+ and it gets more flexible. The people trying to run 1-7GB of memory are going to have data loss.

Sent from my Nexus 5X using Tapatalk
 
Status
Not open for further replies.
Top