public Builder setTtl(com.google.protobuf.Duration value) {
      if (ttlBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        ttl_ = value;
      } else {
        ttlBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
Optional. TTL for the backup to expire. Value range is 1 day to 100 years.
If not specified, the default value is 100 years.
</pre>

<code>.google.protobuf.Duration ttl = 2 [(.google.api.field_behavior) = OPTIONAL];</code>
java-valkey/proto-google-cloud-valkey-v1/src/main/java/com/google/cloud/memorystore/v1/BackupInstanceRequest.java