[skywalking] 01/01: Fill my FAQ reply in official document.

[wu...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

wusheng pushed a commit to branch faq-mq
in repository https://gitbox.apache.org/repos/asf/skywalking.git

commit 637f00b1d70d5e0dd49d369aa828f237f75d300f
Author: Wu Sheng <wu...@foxmail.com>
AuthorDate: Tue Sep 10 14:45:33 2019 -0700

    Fill my FAQ reply in official document.
---
 docs/en/FAQ/README.md                    |  3 +++
 docs/en/FAQ/why_mq_not_involved.md       | 23 +++++++++++++++++++++++
 docs/en/concepts-and-designs/overview.md |  1 +
 3 files changed, 27 insertions(+)

diff --git a/docs/en/FAQ/README.md b/docs/en/FAQ/README.md
index ec9addc..a469c55 100644
--- a/docs/en/FAQ/README.md
+++ b/docs/en/FAQ/README.md
@@ -1,6 +1,9 @@
 # FAQs
 These are known and common FAQs. We welcome you to contribute yours.
 
+## Design
+* [Why doesn't SkyWalking involve MQ in the architecture?](why_mq_not_involved.md)
+
 ## Compiling
 * [Protoc plugin fails in maven build](Protoc-Plugin-Fails-When-Build.md)
 * [Required items could not be found, when import project into Eclipse](Import-Project-Eclipse-RequireItems-Exception.md)
diff --git a/docs/en/FAQ/why_mq_not_involved.md b/docs/en/FAQ/why_mq_not_involved.md
new file mode 100644
index 0000000..eb63864
--- /dev/null
+++ b/docs/en/FAQ/why_mq_not_involved.md
@@ -0,0 +1,23 @@
+# Why doesn't SkyWalking involve MQ in the architecture?
+People usually ask about these questions when they know SkyWalking at the first time.
+They think MQ should be better in the performance and supporting high throughput.
+Here are the reasons the SkyWalking's opinions.
+
+### Is MQ a good or right way to community with OAP backend?
+This question comes out when people think about what happens when the OAP cluster is not powerful enough or offline. 
+But I want to ask the questions before answer this.
+1. Why do you think OAP should be not powerful enough? As it is not, the speed of data analysis wouldn't catch up with producers(agents). Then what is the point of adding new deployment requirement?
+1. Maybe you will argue says, the payload is sometimes higher than usual as there is hot business time. But, my question is how much higher? 
+1. If less than 40%, how many resources will you use for the new MQ cluster? How about moving them to new OAP and ES nodes?
+1. If higher than 40%, such as 70%-2x times? Then, I could say, your MQ wastes more resources than it saves. 
+Your MQ would support 2x-3x payload, and with 10%-20% cost in general time. Furthermore, in this case, 
+if the payload/throughput are so high, how long the OAP cluster could catch up. I would say never before it catches up, the next hot time event is coming.
+
+Besides all this analysis, why do you want the traces still 100%, as you are costing so many resources? 
+Better than this, 
+we could consider adding a better dynamic trace sampling mechanism at the backend, 
+when throughput goes over the threshold, active the sampling rate to 100%->10% step by step, 
+which means you could get the OAP and ES 3 times more powerful than usual, just ignore the traces at hot time.
+
+### How about MQ metrics data exporter?
+I would say, it is already available there. Exporter module with gRPC default mechanism is there. It is easy to provide a new implementor of that module.
\ No newline at end of file
diff --git a/docs/en/concepts-and-designs/overview.md b/docs/en/concepts-and-designs/overview.md
index 09129f3..a663604 100644
--- a/docs/en/concepts-and-designs/overview.md
+++ b/docs/en/concepts-and-designs/overview.md
@@ -42,3 +42,4 @@ Sharding-Sphere, or implement your own. Of course, we are very appreciated to ha
 
 ## What is next?
 - Learn SkyWalking's [Project Goals](project-goals.md)
+- FAQ, [Why doesn't SkyWalking involve MQ in the architecture?](../FAQ/why_mq_not_involved.md)