@Override
    public int hashCode() {
        return Objects.hash(id,
                version,
                createTimeMs,
                createUser,
                updateTimeMs,
                updateUser,
                path,
                nodeName,
                state,
                bytesLimit,
                bytesUsed,
                bytesFree,
                bytesTotal,
                statusMs,
                indexVolumeGroupId);
    }
@return The path the volume resides in. This may be a relative path in which case
it should be resolved relative to stroom.home before use.
stroom-core-shared/src/main/java/stroom/index/shared/IndexVolume.java