[skywalking] 01/01: Update backend-setup.md

[wu...@apache.org]

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wusheng pushed a commit to branch wu-sheng-patch-1
in repository https://gitbox.apache.org/repos/asf/skywalking.git

commit f76e6c2c154135bc66a7d2fdbc221a65a11df794
Author: 吴晟 Wu Sheng <wu...@foxmail.com>
AuthorDate: Sun Jan 19 16:58:58 2020 +0800

    Update backend-setup.md
---
 docs/en/setup/backend/backend-setup.md | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/docs/en/setup/backend/backend-setup.md b/docs/en/setup/backend/backend-setup.md
index 3168565..f006be2 100755
--- a/docs/en/setup/backend/backend-setup.md
+++ b/docs/en/setup/backend/backend-setup.md
@@ -80,8 +80,7 @@ rules targeting the analysis oal metrics objects.
 scale and support high payload, you may need this. 
 1. [Metrics exporter](metrics-exporter.md). Use metrics data exporter to forward metrics data to 3rd party
 system.
-1. [Time To Live (TTL)](ttl.md). Metrics and trace are time series data, they would be saved forever, you could 
-set the expired time for each dimension.
+1. [Time To Live (TTL)](ttl.md). Metrics and trace are time series data, TTL settings affect the expired time of them.
 1. [Dynamic Configuration](dynamic-config.md). Make configuration of OAP changed dynamic, from remote service
 or 3rd party configuration management system.
 1. [Uninstrumented Gateways](uninstrumented-gateways.md). Configure gateways/proxies that are not supported by SkyWalking agent plugins,