# 2021-04-11-15:55:43+0800 tunning PD store-limit configuration for customer

- Cause: A customer scaled their cluster (id: 1311285575352848384) but the scaling process is too slow, we tune the PD parameters to accelerate this process
- Operation:

```
> kubectl exec -it -n tidb1311285575352848384 db-pd-0 -- sh
> cd /var/lib/pd-tls
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653169 30
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653170 30
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653171 30
# witness a while
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653169 45
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653170 45
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653171 45
```

- Impact: The scaling process (migrate date regions) will be accelerated, correspondingly, the CPU usage of TiKV nodes will increase.
- Recovery operation: set the limit to the default value 15

```
> kubectl exec -it -n tidb1311285575352848384 db-pd-0 -- sh
> cd /var/lib/pd-tls
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653169 15
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653170 15
> /pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit 4653171 15
```
- Time window: 19:52:00~20:12:00 CST, April 10