LUKS/ dm-crypt/ ext4 appears to be single threaded

[David Christensen]

freebsd-questions:

Thread moved from debian-user and dm-crypt.

     http://lists.debian.org/debian-user/2012/03/msg01154.html

     http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/5724


I seem to recall FreeBSD having encrypted disks/ filesystems/ whatever. 
  Is there one that is multi-threaded?


TIA,

David



I have a 1.5 TB SATA hard drive I use for back-up's.  It has a single
large partition encrypted with LUKS/ dm-crypt and formatted with ext4.
I've noticed what appears to be single-threaded behavior when one
process is performing a long-lived write to the disk (notably 'ssh
user at host tar ... > backupfile.tar.gz') and another process attempts to
access the disk (either read or write).  This is tolerable for a back-up 
application, but would not be acceptable for multi-user, multi-process, 
and/or multi-threaded applications (file server, terminal server, web 
server, etc.).


Is this a fundamental limitation of LUKS, dm-crypt, and/or ext4, or
something I've configured/ misconfigured?


If a fundamental limitation, is there something I can substitute to
eliminate the problem?


Some manufacturers make hard drives with built-in encryption.  Are these 
supported by Debian, Linux, or BSD?

     http://www.seagate.com/www/en-us/products/self-encrypting-drives/


Any other comments or suggestions?


TIA,

David