Chapter 7. Use cases 183
Spectrum Scale enforces the existence of the files that were created on the Power Systems 
cluster in the AWS cluster, as shown in Example 7-23. Spectrum Scale also updates the 
writes on both clusters (sides). There is a prefetch command that brings all the data before,; 
therefore, only the changes are updated after prefetch is done. This makes accessing the full 
database faster in the cloud.
Example 7-23   Files as a cache and prefetched in the cloud
[root@ip-10-0-2-217 ~]# ls -la /gpfs/mongoafm/mongo/
total 146083
drwx------. 4 mongo mongo      8192 Nov  9 16:59 .
drwxr-xr-x. 7 root  root       4096 Oct 31 12:28 ..
-rw-------. 1 mongo root      16384 Nov  9 14:38 
collection-0--1629751576978663310.wt
-rw-------. 1 mongo root      36864 Nov  9 16:58 
collection-0-7744448727083060016.wt
-rw-------. 1 mongo root      32768 Nov  9 14:39 
collection-2--1629751576978663310.wt
-rw-------. 1 mongo root  145391616 Nov  9 16:24 
collection-3-7744448727083060016.wt
-rw-------. 1 mongo root      16384 Nov  9 14:38 
collection-4--1629751576978663310.wt
drwx------. 2 mongo root       8192 Nov 10 12:01 diagnostic.data
-rw-------. 1 mongo root      16384 Nov  9 14:38 index-1--1629751576978663310.wt
-rw-------. 1 mongo root      36864 Nov  9 16:58 index-1-7744448727083060016.wt
-rw-------. 1 mongo root      36864 Nov  9 16:58 index-2-7744448727083060016.wt
-rw-------. 1 mongo root      32768 Nov  9 14:39 index-3--1629751576978663310.wt
-rw-------. 1 mongo root    3735552 Nov  9 16:24 index-4-7744448727083060016.wt
-rw-------. 1 mongo root      16384 Nov  9 14:38 index-5--1629751576978663310.wt
-rw-------. 1 mongo root      16384 Nov  9 15:27 index-6--1629751576978663310.wt
drwx------. 2 mongo root       8192 Nov  9 16:23 journal
-rw-------. 1 mongo root      36864 Nov  9 15:31 _mdb_catalog.wt
-rw-------. 1 mongo root          2 Nov  9 14:38 mongod.lock
-rw-------. 1 mongo root      36864 Nov  9 16:59 sizeStorer.wt
-rw-------. 1 mongo root        114 Nov  9 14:38 storage.bson
-rw-------. 1 mongo root         48 Nov  9 14:38 WiredTiger
-rw-------. 1 mongo root       4096 Nov  9 14:38 WiredTigerLAS.wt
-rw-------. 1 mongo root         21 Nov  9 14:38 WiredTiger.lock
-rw-------. 1 mongo root       1049 Nov  9 16:59 WiredTiger.turtle
-rw-------. 1 mongo root      69632 Nov  9 16:59 WiredTiger.wt
Check that the link to the Persistent Volume claim was created, bound to the PV that was just 
created, and also applied the file, as shown in Example 7-24.
Example 7-24   Persistent volume claim yaml file
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: appmongo-ibm-mongodb-dev-datavolume
spec:
  storageClassName: manual
  accessModes:
  - ReadWriteMany
  resources:
    requests: