// to attempt a heal on the object.
		if countErrs(errs, errDiskNotFound) > 0 {
			return
		}

		var missingBlocks int
		for i := range errs {
			if IsErr(errs[i],
				errFileNotFound,
				errFileVersionNotFound,
				errFileCorrupt,
			) {
				missingBlocks++
			}
		}

		// if missing metadata can be reconstructed, attempt to reconstruct.

	},
	ErrCastFailed: {
		Code:           "CastFailed",
		Description:    "Attempt to convert from one data type to another using CAST failed in the SQL expression.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidCast: {
		Code:           "InvalidCast",
		Description:    "Attempt to convert from one data type to another using CAST failed in the SQL expression.",

	}

	wk, err := workers.New(workerSize)
	if err != nil {
		// invalid worker size.
		return err
	}

	retryAttempts := ri.RetryAttempts
	retry := false
	for attempts := 1; attempts <= retryAttempts; attempts++ {
		attempts := attempts
		// one of source/target is s3, skip delete marker and all versions under the same object name.