SSD or HDD?

[Pierce]

I find memory is the biggest problem. As long as your storage is ok.

As you get busier the more php threads you need and at 512mb/ thread memory demands can increase exponentially.

Mysqld is also the other monster that needs memory using ssd access is fast but still slows down.

 

[Mike Edge]

I find memory is the biggest problem. As long as your storage is ok.

As you get busier the more php threads you need and at 512mb/ thread memory demands can increase exponentially.

Mysqld is also the other monster that needs memory using ssd access is fast but still slows down.

Agree, we need a lot of RAM per server too as we offer Memcache and Elastic Search to all our clients as well.

 

[zoldos]

I use PHP 7's built in opcache. I hear XF is supposedly to natively support it.

 

[Anthony Parsons]

Mysqld is also the other monster that needs memory using ssd access is fast but still slows down.

Nope... not really. You can actually get sql queries to function better with minimal memory than more, especially with SSD. Get a linux optimisation expert...

My server footprint has shifted from a load average of 3.00, spiking to 6, to around 1.3, spiking to 2.8, just from correctly tweaking query response time from expert analysis. Let me tell you, I was shocked when reducing things gave better server, and user, performance.

Holding more in memory is not as optimal as you may think.

 

[Pierce]

I can only talk from my own experience and from what I've read.

The primary point is to have the indexs in memory at least. The rest is not so important then.

Mine never goes above one even at peek (1800 online member/guest/robots).

Before xenforo I kept the attachments as blob and the database was 60gb or so.

Probably not the smartest but I learned a lot looking after a db.

 

[Mouth]

correctly tweaking query response time

The primary point is to have the indexs in memory at least. The rest is not so important then.

Best query response time, for reads, will come from in-memory data - either sql or redis/memcache.
Tweaking for disk based reads or indexes only, instead of correctly configured in-memory usage/allowance, won't get best performance.