[linux-lvm] Re: Device-mapper submission for 2.4
Jord Tanner
jord at indygecko.com
Fri Dec 12 11:23:01 UTC 2003
Device Mapper 1.00.07 patches against 2.4.23 with no problems. Follow
the directections for device mapper at
http://evms.sourceforge.net/install/kernel.html
Jord Tanner
Yanick Quirion wrote:
>Hi,
>
>Is there a patch for device-mapper for kernel 2.4.23?
>
>Thanks
>
>Yanick
>
>
>
>>-----Original Message-----
>>From: Alasdair G Kergon [mailto:agk at uk.sistina.com]
>>Sent: 11 December, 2003 14:48
>>To: linux-kernel at vger.kernel.org; linux-lvm at sistina.com
>>Cc: Paul Jakma; Mike Fedyk; Joe Thornber; Marcelo Tosatti; Linus
>>
>>
>Torvalds
>
>
>>Subject: [linux-lvm] Re: Device-mapper submission for 2.4
>>
>>On Wed, Dec 10, 2003 at 03:40:07PM -0800, Mike Fedyk wrote:
>>
>>
>>>On Wed, Dec 10, 2003 at 05:00:43PM +0000, Paul Jakma wrote:
>>>
>>>
>>>>On Wed, 10 Dec 2003 venom at sns.it wrote:
>>>>
>>>>
>>>>>DM is back compatible with LVM1, tested and runs well.
>>>>>
>>>>>
>>>>What about the patches posted by Joe last (?) week which remove
>>>>
>>>>
>LVM1
>
>
>>>>support from 2.6 DM?
>>>>
>>>>
>>They remove support for the broken version 1 of the device-mapper
>>ioctl interface. This is nothing to do with LVM1.
>>
>>
>>
>>>If this is what I was reading being discussed a few weeks ago, then
>>>
>>>
>the
>
>
>>>support for the LVM1 sysctls/ioctls has/will be removed, so you will
>>>
>>>
>>have to
>>
>>
>>>use the DM utilities instead of the old LVM1 utilities. LVM1
>>>
>>>
>on-disk
>
>
>>format
>>
>>
>>>should still be supported.
>>>
>>>
>>2.6 does not support LVM1 ioctls.
>>LVM2 userspace tools and EVMS both support LVM1 on-disk format using
>>device-mapper.
>>
>>
>>Here's a reference sheet to help clarify the terminology and explain
>>what's happening.
>>
>>LVM1 = Userspace tools + kernel ioctls included in marcelo's 2.4 tree
>> - LVM1 kernel ioctls are *not* included in or available for 2.6
>> - LVM1 userspace tools do *not* work with 2.6 kernels
>>
>>dm = Kernel driver (GPL) for new volume managers to use.
>> - Included in Linus's 2.6 kernels.
>> - Available as a patch for 2.4 kernels from the Sistina website.
>> - Knows *nothing* about volume manager's on-disk metadata layouts.
>> - Userspace volume managers (e.g. EVMS and LVM2) communicate via a
>>
>>
>new
>
>
>> ioctl interface.
>> - This ioctl interface is currently "version 4" and we regard it as
>> stable. [Some enhancements are on the horizon, but nothing that
>> breaks existing code/binaries.]
>> - An old development version of this device-mapper ioctl interface
>>
>>
>known
>
>
>> as "version 1" has problems with it, is deprecated and should be
>> removed from kernel trees ASAP.
>> Always use "version 4" when building new kernels today.
>>
>>libdevmapper = Userspace shared library (LGPL) which wraps a volume
>>manager
>> application interface around the device-mapper ioctls
>> - Can determine transparently whether the kernel device-mapper is
>>
>>
>using
>
>
>> "version 4" dm ioctl interface or the deprecated "version 1"
>>
>>
>interface
>
>
>> and adapt itself accordingly. [configure --enable-compat]
>> - Can only communicate with device-mapper: it cannot use LVM1
>>
>>
>ioctls.
>
>
>> - Designed primarily for use by LVM2 tools. [EVMS does not use it]
>> - Some parts of the libdevmapper API are not yet stable and are
>>
>>
>likely
>
>
>> to get changed.
>>
>>dmsetup = Userspace utility (GPL) which provides full command-line
>>
>>
>access
>
>
>>to
>> the libdevmapper API.
>> - Designed for use by shell scripts and for testing and debugging.
>> - Command line interface may be considered stable. New features may
>>
>>
>get
>
>
>> added, but we'll try not to break existing commands.
>>
>>LVM2 = New Logical Volume Manager command line tools (GPL) designed to
>> be backward-compatible with LVM1 and offering new features and
>> more flexibility, configurability and stability.
>> - Supports existing LVM1 on-disk metadata.
>> This means you do *not* have to make changes to your existing
>>
>>
>on-disk
>
>
>> LVM1 volumes to switch between using LVM1 and LVM2.
>> - Uses command lines similar to LVM1.
>> - By default uses a new on-disk metadata format supporting more
>> features than the original LVM1 version.
>> - Communicates with the device-mapper kernel driver via
>>
>>
>libdevmapper's
>
>
>> API.
>>
>>
>>Miscellaneous points:
>> - LVM1 uses block major number 58: dm selects one or more major
>>
>>
>numbers
>
>
>> dynamically as required instead.
>> - LVM1 uses character major number 109: dm selects a misc minor
>>
>>
>number
>
>
>> dynamically instead.
>> - There's a (non-devfs) script for creating /dev/mapper/control at
>> startup (or after dm module load).
>> - You can use LVM1 tools with unpatched 2.4 kernels.
>> - You can use LVM2 tools with patched 2.4 and unpatched 2.6 kernels.
>> - Device-mapper support for snapshots and pvmove is so far released
>> only for 2.4. Patches for 2.6 are being tested.
>> - Multipath and mirror support are under development for 2.6.
>> (Then get back-ported to 2.4.)
>>
>>Web download page: http://www.sistina.com/products_lvm_download.htm
>>
>>The device-mapper tarball contains:
>> device-mapper kernel patches - needed only for 2.4;
>> userspace libdevmapper and dmsetup - needed with all dm kernels.
>>The LVM2 tarball contains the LVM2 command line tools.
>>
>>Development code can be found via:
>> http://people.sistina.com/~thornber/ (for kernel patches)
>> http://www.sistina.com/products_CVS.htm (for userspace code)
>>
>>Device-mapper mailing list:
>> http://lists.sistina.com/mailman/listinfo/dm-devel
>>
>>Alasdair
>>--
>>agk at uk.sistina.com
>>
>>_______________________________________________
>>linux-lvm mailing list
>>linux-lvm at sistina.com
>>http://lists.sistina.com/mailman/listinfo/linux-lvm
>>read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>
>>
>
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>
>
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