On Feb 3, 2012, at 8:20 PM, Bruce Dubbs wrote:
> Qrux wrote:
>> The instructions on the svn LVM2 page could use a bit of updating.
>>
>> The package isn't usable (at least according to docs) without certain
>> options.
>
> I've certainly been able to create, format, and mount an lvm partition...
Fair enough.
>> They're on the page, but they're not in the build commands.
>> Also, there's some nice info in the docs subdir of the tarball that
>> don't get installed.
>>
>> I propose this update to the LVM2 page (including a version bump to
>> LVM2.2.09.90):
>>
>> ====
>> ./configure --prefix=/usr --enable-pkgconfig --enable-dmeventd
>> --enable-cmdlib
>
> When you do that, the only executable added is dmeventd, but the
> executables do link to a new library. The description of dmeventd is
> "the event monitoring daemon for device-mapper devices. Library plugins
> can register and carry out actions triggered when particular events occur."
>
> I have no idea what that means or how it would be used. The fact that
> it's a daemon appears to mean that a boot script needs to be written to
> control it. I'm reluctant to do that unless I know what it does.
>
> If we have a writeup for a separate page "Using LVM" that explains it,
> I'd think the change would be appropriate.
It's sort of hard to find dmeventd information. It's buried in the default
lvm.conf file. I think the main purpose is to allow LVM to handle some errors
automatically. Most of the stuff is in the "Activation" section. Here's one
relevant example that discusses auto-rebuild of a RAID hot-spare:
# 'raid_fault_policy' defines how a device failure in a RAID logical
# volume is handled. This includes logical volumes that have the following
# segment types: raid1, raid4, raid5*, and raid6*.
#
# In the event of a failure, the following policies will determine what
# actions are performed during the automated response to failures (when
# dmeventd is monitoring the RAID logical volume) and when 'lvconvert' is
# called manually with the options '--repair' and '--use-policies'.
#
# "warn" - Use the system log to warn the user that a device in the RAID
# logical volume has failed. It is left to the user to run
# 'lvconvert --repair' manually to remove or replace the failed
# device. As long as the number of failed devices does not
# exceed the redundancy of the logical volume (1 device for
# raid4/5, 2 for raid6, etc) the logical volume will remain
# usable.
#
# "allocate" - Attempt to use any extra physical volumes in the volume
# group as spares and replace faulty devices.
#
raid_fault_policy = "warn"
Not all the dmeventd stuff is strictly LVM related, though asking people to
unpack LVM to install dmeventd for RAID stuff is equally...questionable.
>> LVM2_DOC_DIR=/usr/share/doc/lvm2-2.02.90
>> install -d ${LVM2_DOC_DIR}
>> cp -va doc/* ${LVM2_DOC_DIR}
>> rm -vf ${LVM2_DOC_DIR}/Makefile{,.in}
>
> I'd think this would be better for the last two lines:
>
> cp -v doc/{*.txt,example*} ${LVM2_DOC_DIR}
> Although in the book, for consistency, I'd spell out
> /usr/share/doc/lvm2-2.02.90 in both the install and cp commands.
Don't want the kernel subdir? Maybe:
install -d /usr/share/doc/lvm2-2.02.90
cp -va doc/{kernel,*.txt,example*} /usr/share/doc/lvm2-2.02.90
is better?
Q
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