So is it possible to use Zookeeper + Clickhouse on the same server?

Question

System administration

In the Clickhouse documentation, I often see the warning:

Do not run ZooKeeper on the same servers as ClickHouse. Because ZooKeeper is very sensitive for latency and ClickHouse may utilize all available system resources

[do not use Zookeeper on the same server as Clickhouse because Zookeeper is very latency sensitive].
But I can't understand: delays of what? SSD drives? Processor? Memory? Will I be able to see this problem in time through htop/atop?
I have a fairly small project (statistics for 10 hits per second, 36000 per hour, I think a maximum of two times the increase is possible). Recording in Clickhouse goes centrally through the aggregation of log records and their recording through a single insert.
Can I run into these latency issues with similar workloads?
Because it seems to me that this is unlikely to be a particular problem, and buying another separate server for storing Zookeeper (and in a good way, as many as three, because I need replication) is too much for the budget.
Or can I still run into serious overloads even at this volume?
I understand that the question seems too simple, but I want to play it safe, because. On tests, I'm afraid not to notice problems in time.

Answer 1

performance tests.
You can see for yourself if it works for you or not.
If problems start - you will know that it's time to distribute to different servers, as an officially recommended action

Answer 2

At least very undesirable. Clickhouse loves to eat the processor, and Zookeeper is critical to delays, i.e. if the clickhouse eats up all the CPU time, the zookeeper will start to crash. "To delays" - means processing requests like keepalive, etc., i.e. processor.

Answer 3

In fact, Zookeeper is sensitive to disk latency,
if you have enough CPU and you can put Zookeeper snapshots and logs on a separate ssd disk not connected to clickhouse, then it will work just fine, you can usually
try these ones that appeared in the latest versions of clickhouse-keeper,
but it is very experimental for now
https://clickhouse.com/docs/en/operations/clickhou...
but can run as part of the clickhouse-server process