dev/reference: fix a broken link

Related PR: pingcap/docs-cn#1334

dev/reference/tools/tidb-lightning/deployment.md

@@ -55,7 +55,8 @@ If you have sufficient machines, you can deploy multiple Lightning/Importer serv
 > `tikv-importer` stores intermediate data on the RAM to speed up process. The typical memory usage can be calculated from configuration as **(`max-open-engines` × `write-buffer-size` × 2) + (`num-import-jobs` × `region-split-size` × 2)**. If the speed of writing to disk is slow, the memory usage could be even higher due to buffering.
 
 Additionally, the target TiKV cluster should have enough space to absorb the new data.
-Besides [the standard requirements](/dev/how-to/deploy/hardware-recommendations.md), the total free space of the target TiKV cluster should be larger than **Size of data source × [Number of replicas](/FAQ.md#is-the-number-of-replicas-in-each-region-configurable-if-yes-how-to-configure-it) × 2**.
+Besides [the standard requirements](/dev/how-to/deploy/hardware-recommendations.md), the total free space of the target TiKV cluster should be larger than **Size of data source × [Number of replicas](/faq/tidb.md#is-the-number-of-replicas-in-each-region-configurable-if-yes-how-to-configure-it) × 2**.
+
 With the default replica count of 3, this means the total free space should be at least 6 times the size of data source.
 
 ## Export data