private String getSizeString(final OptionalLong optSizeBytes) {
        return optSizeBytes != null && optSizeBytes.isPresent()
                ? ModelStringUtil.formatIECByteSizeString(optSizeBytes.getAsLong())
                : "?";
    }
Add the columns to the table.
stroom-core-client/src/main/java/stroom/data/store/impl/fs/client/presenter/FsVolumeStatusListPresenter.java