flushall async took 60 seconds in SSD use case when the redis.conf configures 256 databases

When we configure 256 databases in redis.conf and run with the storage provider use case, the flushall async command takes 60 seconds to complete.

To reproduce

1. Set the following parameters in the configuration:

   databases 256
   storage-provider flash /root/data

2. Start the server

3. Run "flushall async" from the cli command line

4. The command takes 60 seconds to complete

Expected behavior

It should take less time to "flushall async" even though the number of databases configured is 256.

Additional information