Re: [dm-crypt] Question on Disk Layout (Stacking supported ?)

[Arno Wagner <arno@wagner.name>]

Don't know about your particlar setup, but I have several
RAID1 (including two 3-way and one with an SSD) below
dm-crypt. Works pretty well. 

The main question I see is what you want with the encrypton.
Of course, you can blanket encrypt everything, wich seems
to be what you want, except for /boot. Personally, I 
want it the other way round, but I have not allways
all encrypted devices mapped and different passphrases
for them.

Arno


On Thu, Mar 10, 2011 at 07:06:31PM +0100, Robert.Heinzmann@deutschepost.de wrote:
> Hello list, 
>  
> I have a more general question regarding dm_crypt. 
>  
>   Q: What is the best way to incorporate dm_crypt in a production ready device stack ? 
> 
> Summing I have multipathing (optional) and I want flexible storage management with pvresize, multiple filesystems and everything (e.g. in "the clouds") LVM is the way to go. So my ideal (and working) setup would look like this: 
>  
> Filesystem: [      /boot      ] [ /   ]  [ /var ]
> LVM         [                 ] [ lv1 ]  [ lv2  ]
> LVM         [                 ] [ vg (RootVG)   ]
> LVM         [                 ] [ pv            ]
> Crypt:      [                 ] [ DM_CRYPT      ] 
> Partition:  [ part1 - (boot)  ] [    part2      ]
> SCSI:       [            Block Device           ] 
> DMMP:       [   Path1         ][    Path2       ]  (Optional Layer)
> Disk:       [            LUN                    ] 
>  
> Do you see any problems (from the dm_crypt side) with this setup in terms of deadlocks, or unsupported stacking  or is this a "supposed to work" configuration ? 
> 
> I know that device mapper always causes performance penalty because of missing barrier support (earlier Kernels) and I/O splitting in 4k units, however I have a BBU, so not a problem really and performance penalty is allowed.
> 
> I have seen that the split to 4k causes latency to increase dramatically, however this seems to be a "minor" issue also (altought no solution so far).
> 
> Mit freundlichen Gr??en / Kind Regards
> Robert Heinzmann
> _______________________________________________
> dm-crypt mailing list
> dm-crypt@saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt
> 

-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier