Additional RAM worthwhile?

[WannabeMKII]

I'm running my unraid on an N54L with 4GB RAM.

 

I currently have 6 docker containers running, no VM's and it serves all my files, media, backups etc.

 

I wondered if I'd see any benefit of doubling the RAM to 8GB?

[tdallen]

My guess is that you’d see some benefit but you won’t be amazed.   - it depends on which Dockers you are running.  What does the Dashboard (or Dynamix System Stats if you are running it) say about your current memory usage?  unRAID caches writes in system memory so my guess is that you would notice the initially faster copies to your server since more memory will be available for caching.

[WannabeMKII]

2 hours ago, tdallen said:

My guess is that you’d see some benefit but you won’t be amazed.   - it depends on which Dockers you are running.  What does the Dashboard (or Dynamix System Stats if you are running it) say about your current memory usage?  unRAID caches writes in system memory so my guess is that you would notice the initially faster copies to your server since more memory will be available for caching.

Here's a screenshot of my RAM. We're streaming a film on the network at the moment.

 

The used is pretty static, but the cached does drop down to about 60% or so when 'resting'...

[CHBMB]

https://www.linuxatemyram.com/

[WannabeMKII]

5 minutes ago, CHBMB said:

https://www.linuxatemyram.com/

Thanks for the info, appreciate how caching works, just wondering if I'd really benefit from more RAM or not.

 

It's been fine the last year or so, just wondered if it was a relatively cheap upgrade to get better performance or not...

[CHBMB]

1 minute ago, WannabeMKII said:

Thanks for the info, appreciate how caching works, just wondering if I'd really benefit from more RAM or not.

 

It's been fine the last year or so, just wondered if it was a relatively cheap upgrade to get better performance or not...

I'm guessing not as you haven't noticed any issues and the amount you've got used as cache is relatively high.

[WannabeMKII]

Just now, CHBMB said:

I'm guessing not as you haven't noticed any issues and the amount you've got used as cache is relatively high.

No worries, I'll leave it as it is and save my money.

 

It's sitting at 44% on the dashboard, so assume that's OK.

 

Thanks again!

[pwm]

3 hours ago, WannabeMKII said:

No worries, I'll leave it as it is and save my money.

 

It's sitting at 44% on the dashboard, so assume that's OK.

 

Thanks again!

For normal media file server use, the OS don't need very much RAM for caching. The media files themselves tends to be huge so they quickly blow through any amount of cache RAM. Well-behaved programs that makes one-pass reads through large files should really specify that the file data shouldn't be buffered just to not evict the file system and directory structure meta data from the cache.

 

If you run a database server on the other hand, you want large amounts of cache since you have pseudo-random accesses to the database and additional cache RAM can greatly increase the number of database transactions per second the machine can manage.