# Some questions about cluster configuration and test

**URL:** <https://forums.foundationdb.org/t/some-questions-about-cluster-configuration-and-test/3255>\
**Category:** Using FoundationDB\
**Created:** [April 8, 2022, 2:41pm UTC](https://forums.foundationdb.org/t/some-questions-about-cluster-configuration-and-test/3255 "2022-04-08T14:41:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![xiaodongzhang97](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/xiaodongzhang97/32/1307_2.png) [@xiaodongzhang97](https://forums.foundationdb.org/u/xiaodongzhang97)\
**Post date:** [April 8, 2022, 2:41pm UTC](https://forums.foundationdb.org/t/some-questions-about-cluster-configuration-and-test/3255/1 "2022-04-08T14:41:05Z")

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I have build a cluster in AWS with following machines and configurations  
M1: m5.4xlarge (16 vcpu + 64GB DRAM)  
M2 & M3: m5.2xlarge (8 vcpu + 32 GB DRAM)  
I use memory storage engine.  
For M1 I set 16 processes with `class=storage` ,`memory = 10GiB`, `storage_memory = 4GiB` and `cache_memory = 1GiB`.  
For M2 I set 8 processes with `class=transaction`.  
For M3 I set 8 processes with `class=stateless`.

My first question is that if I configure the class of process and memory properly.

My second question is that I found there is little operating space left after I create a database. The `status` result is shown following. I want to know what is operating spaces and how to expand it.

```auto
Configuration:
  Redundancy mode - single
  Storage engine - memory-2
  Coordinators - 3
  Usable Regions - 1

Cluster:
  FoundationDB processes - 32
  Zones - 3
  Machines - 3
  Memory availability - 4.1 GB per process on machine with least available
  Fault Tolerance - 0 machines
  Server time - 04/08/22 14:08:23

Data:
  Replication health - Healthy
  Moving data - 0.000 GB
  Sum of key-value sizes - 0 MB
  Disk space used - 316 MB

Operating space:
  Storage server - 0.8 GB free on most full server
  Log server - 3.2 GB free on most full server

Workload:
  Read rate - 37 Hz
  Write rate - 0 Hz
  Transactions started - 10 Hz
  Transactions committed - 0 Hz
  Conflict rate - 0 Hz

Backup and DR:
  Running backups - 0
  Running DRs - 0

```

The third question is that when I try to run a `multitest`, I need to set the class of some processes as `test`.  
The docs said that these processes will act as clients.  
So how many test class processes should I set to get a better test result (higher throughput).

Look forward to anyone’s help.  
Thanks very much!

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**Author:** ![osamarin](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/osamarin/32/905_2.png) [@osamarin](https://forums.foundationdb.org/u/osamarin)\
**Post date:** [April 11, 2022, 8:49am UTC](https://forums.foundationdb.org/t/some-questions-about-cluster-configuration-and-test/3255/2 "2022-04-11T08:49:34Z")

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> My second question

For the `memory` storage engine the operating space is set with the parameter `storage_memory`. The default value is 1GiB.

See more details at [Configuration — FoundationDB 7.1](https://apple.github.io/foundationdb/configuration.html#fdbserver-section)

> `storage_memory = 4GiB` and `cache_memory = 1GiB` .

Seems you have set `storage_memory = 1GiB` and `cache_memory = 4GiB` .

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**Author:** ![osamarin](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/osamarin/32/905_2.png) [@osamarin](https://forums.foundationdb.org/u/osamarin)\
**Post date:** [April 11, 2022, 8:57am UTC](https://forums.foundationdb.org/t/some-questions-about-cluster-configuration-and-test/3255/3 "2022-04-11T08:57:35Z")

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> [@xiaodongzhang97](#):
>
> My first question is that if I configure the class of process and memory properly.

If you specify `memory = 10Gib` then 16 storage processes will require up to 160 Gib but you have only 64Gib of RAM. This configuration is not stable.

But having 6 Gib above the `cache_memory` for storage processes are extra. Most of additional memory is required for universal processes, but not for dedicated storage processes.

So if you have `cache_memory = 4 Gib`, then `memory = 6 Gib` is enouth for storage processes. So you need to have 16\*6Gib + 2 Gib = 98 Gib memory for M1 machines

You haven’t written how many machines of each type do you have. If you have only 3 machines, one machine of each type, then placing all process classes on one machine is not good from the availability point of view: your cluster can not continue after failing of any machine.

Another point is one transaction process can handly about 8 storage processes. So if you have 16 storage processes, then 2 transaction processes would be enough.

So I’d recommend you

- To have 3 similar machines with 8 cpu and 64 GB RAM

- or to have 15 small machines (2 CPU, 14 GB RAM)

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**Author:** ![xiaodongzhang97](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/xiaodongzhang97/32/1307_2.png) [@xiaodongzhang97](https://forums.foundationdb.org/u/xiaodongzhang97)\
**Post date:** [April 12, 2022, 10:45am UTC](https://forums.foundationdb.org/t/some-questions-about-cluster-configuration-and-test/3255/4 "2022-04-12T10:45:47Z")

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Thanks for your patient reply! It helps me a lot.