zevo with Truecrypt volume

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Re: zevo with Truecrypt volume

Post by grahamperrin » Tue Oct 16, 2012 2:14 am

At viewtopic.php?p=954#p954

Shaman wrote:… Is this a known bug/issue?


Let's see whether pools created with TrueCrypt with ZEVO are problematic …
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Re: zevo with Truecrypt volume

Post by grahamperrin » Tue Oct 16, 2012 3:39 pm

No problem here with TrueCrypt 7.1a (also known as 7.1.1) on FUSE for OS X 2.5.2 on OS X 10.8.2.

In the example below I give disk8 (created by TrueCrypt) to ZEVO.

Code: Select all
macbookpro08-centrim:~ gjp22$ diskutil list disk8
/dev/disk8
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.0 MB   disk8
macbookpro08-centrim:~ gjp22$ sudo zpool showdisks
Password:
macbookpro08-centrim:~ gjp22$ zpool create truecrypt-example /dev/disk8
could not create pool: permission denied
macbookpro08-centrim:~ gjp22$ sudo zpool create truecrypt-example /dev/disk8
invalid vdev specification
use '-f' to override the following errors:
/dev/disk8 is in use by filesystem at "/Volumes/untitled"
macbookpro08-centrim:~ gjp22$ diskutil unmountDisk /dev/disk8
Unmount of all volumes on disk8 was successful
macbookpro08-centrim:~ gjp22$ sudo zpool create truecrypt-example /dev/disk8
macbookpro08-centrim:~ gjp22$ zpool status truecrypt-example
  pool: truecrypt-example
 state: ONLINE
 scan: none requested
config:

   NAME                                         STATE     READ WRITE CKSUM
   truecrypt-example                            ONLINE       0     0     0
     GPTE_FA987EE4-3883-474A-867A-44218BED8998  ONLINE       0     0     0  at disk8s1

errors: No known data errors
macbookpro08-centrim:~ gjp22$ diskutil list disk8
/dev/disk8
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme untitled               *524.0 MB   disk8
   1:                        ZFS                         524.0 MB   disk8s1
macbookpro08-centrim:~ gjp22$ zpool export truecrypt-example
macbookpro08-centrim:~ gjp22$ mount | grep osxfusefs


After the disk is given to ZEVO, no problem. Mount in TrueCrypt is followed automatically by import of the pool.
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TrueCrypt disks unlabelled, without a partitioning scheme

Post by grahamperrin » Thu Oct 18, 2012 9:34 pm

Incidentally, focusing on the period before a disk created by TrueCrypt is given to ZEVO:

  • whilst it's possible to create a 'disk' without a file system, TrueCrypt (naturally) can't mount the end result – I don't know whether this type of image can be a foundation for ZEVO
  • accepting the TrueCrypt defaults for Mac OS Extended produces a disk that is unlabelled – no partitioning scheme.

Example:

Code: Select all
sh-3.2$ diskutil list /dev/disk12
/dev/disk12
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *261.9 MB   disk12
sh-3.2$ diskutil info /dev/disk12
   Device Identifier:        disk12
   Device Node:              /dev/disk12
   Part of Whole:            disk12
   Device / Media Name:      Apple read/write Media

   Volume Name:              untitled
   Escaped with Unicode:     untitled

   Mounted:                  Yes
   Mount Point:              /Volumes/untitled
   Escaped with Unicode:     /Volumes/untitled

   File System Personality:  Journaled HFS+
   Type (Bundle):            hfs
   Name (User Visible):      Mac OS Extended (Journaled)
   Journal:                  Journal size 8192 KB at offset 0x4000
   Owners:                   Disabled

   Content (IOContent):      None
   OS Can Be Installed:      No
   Media Type:               Generic
   Protocol:                 Disk Image
   SMART Status:             Not Supported
   Volume UUID:              C13CADC8-F4BA-3475-A7A9-F75B2625150E

   Total Size:               261.9 MB (261881856 Bytes) (exactly 511488 512-Byte-Blocks)
   Volume Free Space:        247.3 MB (247332864 Bytes) (exactly 483072 512-Byte-Blocks)
   Device Block Size:        512 Bytes

   Read-Only Media:          No
   Read-Only Volume:         No
   Ejectable:                Yes

   Whole:                    Yes
   Internal:                 No
   OS 9 Drivers:             No
   Low Level Format:         Not supported

sh-3.2$ hdiutil info
framework       : 344
driver          : 10.7v344
================================================
image-path      : /var/folders/g_/…redacted…/T//.truecrypt_aux_mnt1/volume.dmg
image-alias     : /private/var/folders/g_/…redacted…/T/.truecrypt_aux_mnt1/volume.dmg
shadow-path     : <none>
icon-path       : /System/Library/PrivateFrameworks/DiskImages.framework/Resources/CDiskImage.icns
image-type      : read/write
system-image    : false
blockcount      : 511488
blocksize       : 512
writeable       : TRUE
autodiskmount   : TRUE
removable       : TRUE
image-encrypted : false
mounting user   : gjp22
mounting mode   : <unknown>
process ID      : 77009
/dev/disk12      /Volumes/untitled
sh-3.2$ mount | grep fuse
TrueCrypt@osxfuse0 on /private/var/folders/g_/…redacted…/T/.truecrypt_aux_mnt1 (osxfusefs, nodev, nosuid, synchronous, nobrowse, mounted by gjp22)
sh-3.2$ date
Fri 19 Oct 2012 03:34:05 BST
sh-3.2$ sw_vers
ProductName:   Mac OS X
ProductVersion:   10.8.2
BuildVersion:   12C60
sh-3.2$
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Re: TrueCrypt disks unlabelled, without a partitioning schem

Post by jsb204 » Sat Oct 20, 2012 6:55 pm

grahamperrin wrote:Incidentally, focusing on the period before a disk created by TrueCrypt is given to ZEVO:

  • whilst it's possible to create a 'disk' without a file system, TrueCrypt (naturally) can't mount the end result – I don't know whether this type of image can be a foundation for ZEVO

It isn't a problem, you have to check the (poorly named) "do not mount" option when mounting in TrueCrypt. On the command line I believe the option is "--filesystem=none." That way the decrypted volume will be attached but no attempt will be made to find a filesystem on it, therefore no error will be generated.
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TrueCrypt: to not mount, click Mount

Post by grahamperrin » Sun Oct 21, 2012 12:56 am

Ah, thanks. So TrueCrypt's default Mount button … 

Mount.png
Mount.png (57.71 KiB) Viewed 126 times


… is the starting point for not mounting a file system ;-)
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Re: zevo with Truecrypt volume

Post by grahamperrin » Sun Oct 21, 2012 1:08 am

With ZEVO Community Edition 1.1.1, please avoid the TrueCrypt 7.1.1 option

[*] Mount volume as read-only

Reason 1

TrueCrypt can not attach the disk image to the operating system – two disks are added at /dev (one of which includes the zfs_pool_proxy) but there is no import of the ZFS pool, no mount of the file system.

Then neither TrueCrypt nor diskutil can effectively unmount those disks.

Reason 2

Obscure and avoidable: mds kernel panic with -o readonly=on (TrueCrypt scenario).
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FUSE for OS X 2.5.3 developer preview

Post by grahamperrin » Fri Oct 26, 2012 2:07 pm

With FUSE for OS X 2.5.3 developer preview, osxfusefs volumes mounted by TrueCrypt can be unmounted much more quickly than with release 2.5.2.

Side note, not specific to 2.5.3: the Dismount option in TrueCrypt can not unmount after mounting a volume that is used by ZEVO. It's necessary to eject the user-visible file system (the zfs_pool_proxy) before TrueCrypt can 'Dismount' the underlying disk with the ZFS slice.
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