tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

NetBSD LVM SoC project

Hi, folks

We (I and martin@) are working on NetBSD LVM support. Basically it is device-mapper driver written from scratch. We decided to go this way because it seems to be easiest way to get LVM functionality to NetBSD. Also Linux lvm2tools and libdevmapper are well tested and they are use in production.

Linux LVM has 3 parts: device-mapper driver, libdevmapper library and lvm2tools.

Device-mapper driver maps logical blocks to physical blocks with predefined strategy called "target". Communication protocol between libdevmapper and device-mapper is defined as number of ioctl calls.

LVM2 tools do most of magic what is needed to get LVM properly done. lvm2tools create physical volumes, volume groups and logical volumes(logical disks). Only Logical volumes go through
device-mapper driver.

2) Actual device-mapper driver status

We have implemented ioctl interface with some minor cases which are not needed now. We have working zero and error targets(they are only made for testing;). We are looking to get linear target done
before SoC application starts.

3) SoC tasks

Want to do

3.1) import device-mapper, lvm2tools into NetBSD base system. Get lvm2tools into useable state.
   LVM2tools are ported but doesn't work now.

3.2) change standard ioctl interface to use proplib in our tree. I think this is way to go because actual ioctl interface is really messy. In this task I have to change 2 files in libdevmapper dmsetup/dmsetup.c and lib/ioctl/libdm-iface.c and our device- mapper driver.

3.3) Improve and test our device-mapper code. Probably with ATF test suite.

3.4) Write documentation and import it into htdocs.

 If time permits tasks

3.1) multipath target used for mutlipathing devices.

3.2) clustered LVM.

My time plan is this

In first part of SoC timeframe work on LVM2tools integration and device-mapper bug fixes.

After first Mid-term evaluations deadline I want to work on proplib interface and get it done.

In August 18 I want to start with writing documentation and if time permits I want to look at clusterlvm.

I'm attaching more detailed file to this mail.

Attachment: soc_lvm.pdf
Description: Adobe PDF document



Attachment: PGP.sig
Description: This is a digitally signed message part

Home | Main Index | Thread Index | Old Index