}
if (_storage != null) {
throw new IllegalStateException("This volume has already been opened");
}
if (_specification.getPageSize() <= 0) {
throw new UnderSpecifiedVolumeException(getName());
}
if (persistit.getBufferPool(_specification.getPageSize()) == null) {
throw new BufferSizeUnavailableException(getName());
}
final boolean exists = VolumeHeader.verifyVolumeHeader(_specification, persistit.getCurrentTimestamp());