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

David Christensen dpchrist at
Sun Mar 25 19:49:39 UTC 2012


Thread moved from debian-user and dm-crypt.

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



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?

Any other comments or suggestions?



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