Hello to all, im installing a load balancer and i want to run multiple unbound instances, im doing this because my it experts says it is not recommended to have a huge cache (i have 32GB available) it is better to have 2 or 3 GB cache in multiple unbound instances, this is good for high availability too, so if a instances dies the balancer notices it and the other instances take the load, what do you think about it ? if this a is a good idea, how to run multiple unbound instances, i am running unbound 1.5.1 Centos 6.7.
regards.
Miguel Miranda via Unbound-users:
Hello to all, im installing a load balancer and i want to run multiple
unbound instances, im doing this because my it experts says it is not
recommended to have a huge cache (i have 32GB available) it is better to
have 2 or 3 GB cache in multiple unbound instances, this is good for high
availability too, so if a instances dies the balancer notices it and the
other instances take the load, what do you think about it ? if this a is
a good idea, how to run multiple unbound instances, i am running unbound
1.5.1 Centos 6.7.
regards.
running multiple instances is possible - I do so.
But because of different configurations.
could your "it experts" prove the statement
"it is not recommended to have a huge cache"
somehow?
Andreas
well, we have google, youtube, akamai, netflix caches so they say it is better to have a pool of caches like this providers do, they say the cost of search an asset in a huge (10GB or so) cache is not better than search it from the internet itself, i have not seen numbers that prove this but they say “the exerts at google knows better”
Zitat von Miguel Miranda via Unbound-users <unbound-users@unbound.net>:
Hello to all, im installing a load balancer and i want to run multiple
unbound instances, im doing this because my it experts says it is not
recommended to have a huge cache (i have 32GB available) it is better to
have 2 or 3 GB cache in multiple unbound instances, this is good for high
availability too, so if a instances dies the balancer notices it and the
other instances take the load, what do you think about it ? if this a is
a good idea, how to run multiple unbound instances, i am running unbound
1.5.1 Centos 6.7.
regards.
I would not suspect that the cache size would be a limiting factor for Unbound. It *can* be problematic if you need a lot of CPU power and therefore have a lot (>> 8) of threads using the same cache because of lock contention.
For details have a look here : http://www.unbound.net/documentation/howto_optimise.html
If you need high availability multiple instances will not help that much if they use the same kernel and/or the same hardware, so you have to split the multiple instances on multiple machines and maybe even different OS.
Regards
Andreas
OK thanks. I have read the performance doc, So I have two servers that are serving 250k customers, it is recommended that I configure 10g for cache in one instance? I have 16 cores (with hyper threading) in each one. Should I configure 8 or 16 threads?
Zitat von Miguel Miranda <miguel.mirandag@gmail.com>:
OK thanks. I have read the performance doc, So I have two servers that are
serving 250k customers, it is recommended that I configure 10g for cache
in one instance? I have 16 cores (with hyper threading) in each one.
Should I configure 8 or 16 threads?
I would use 8 threads at max. The "hyperthreading" cores are limited in its use and especially if your 8 cores/threads are not enough they will not help at all.
Regards
Andreas