public void initCacheFromBackupFile() {
    long aMonthAgo = SystemTime.getInstance().seconds() - TimeUnit.DAYS.toSeconds(30);
    Collection<Account> accounts = backupFileManager.getLatestAccounts(aMonthAgo);
    AccountInfoMap accountInfoMap = null;
    if (accounts != null) {
      try {
        accountInfoMap = new AccountInfoMap(accounts);
      } catch (Exception e) {
        logger.warn("Failure in parsing of Account Metadata from local backup file", e);
      }
    }
    if (accountInfoMap == null) {
      accountInfoMap = new AccountInfoMap(accountServiceMetrics);
    }
    // Refresh last modified time of Accounts and Containers in cache
    accountInfoMap.refreshLastModifiedTime();
    accountInfoMapRef.set(accountInfoMap);
  }
Initializes in-memory {@link AccountInfoMap} with accounts and containers stored in backup copy on local disk.
ambry-account/src/main/java/com/github/ambry/account/CachedAccountService.java