kubernetes persistent volume overrides the previous volume - kubernetes

Question

We are trying to run blockchain node with AWS EKS.
We need to maintain the previous blockchain snapshot while updating node version.
So we used the kubernetes persistent volume, but the previous volume is just overwritten whenever we kill the previous pod, and restart the new one.
We set up the arguments of docker image to store the data at "/data/headless"
like this
--store-path=/data/headless
also, we set the volumeMounts to "/disk"
volumeMounts:
- name: block-data
mountPath: /disk
and the result shows
We think this volume path seems a temporary volume, and we are wondering about how to maintain these volumes even if we update the pods.
[We have seen millions of documents of AWS, but still doesn't know where to get started:( ]
How can I update the previous volume and connect it to new pod without losing any data in the previous one?
Here's our source code.
Volume Claim Yaml File
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: nine-claim-3
spec:
storageClassName: gp2
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi
StatefulSet & Service Yaml File
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: nine-cluster
namespace: test-nine-3
labels:
app: nine
spec:
serviceName: nine-cluster
replicas: 2
selector:
matchLabels:
app: nine
template:
metadata:
labels:
app: nine
spec:
containers:
- name: nine-container
image: planetariumhq/ninechronicles-headless:v100260
ports:
- name: rpc
containerPort: 31238
- name: iceserver
containerPort: 3478
- name: peer
containerPort: 31234
- name: graphql
containerPort: 80
args: [
"--port=31234",
"--no-miner",
"--store-type=rocksdb",
"--store-path=/data/headless",
"--graphql-server",
"--graphql-host=0.0.0.0",
"--graphql-port=80",
"--rpc-server",
"--rpc-remote-server",
"--rpc-listen-host=0.0.0.0",
"--rpc-listen-port=31238",
"--no-cors",
"--chain-tip-stale-behavior-type=reboot"
]
volumeMounts:
- name: block-data
mountPath: /data/headless
volumes:
- name: block-data
persistentVolumeClaim:
claimName: nine-claim-3
---
apiVersion: v1
kind: Service
metadata:
name: nine-nlb-services
namespace: test-nine-3
annotations:
service.beta.kubernetes.io/aws-load-balancer-type: nlb
service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: instance
service.beta.kubernetes.io/aws-load-balancer-scheme: internet-facing
spec:
ports:
- name: graphql
port: 80
targetPort: 80
nodePort: 31003
protocol: TCP
- name: rpc
port: 31238
targetPort: 31238
nodePort: 31004
protocol: TCP
type: LoadBalancer
selector:
app: nine