Comment # 11 on bug 982329 from Manfred Hollstein

(In reply to Liuhua Wang from comment #9)
> (In reply to Manfred Hollstein from comment #6)
> > FWIW2: I just tried to reject /dev/loop devices from lvm's filter by adding
> > 
> >   "r|/dev/loop.*|", 
> > 
> > to devices/filter in /etc/lvm/lvm.conf, set max_loop to 64, rebuilt
> > everything required, rebooted and failed again. Even if the /dev/loop
> > devices are explicitly excluded in lvm.conf, they appear to be scanned when
> > the system is booted, and 64 non-existing loop devices appear to be too many
> > to allow the dm/udev logic in the latest lvm2 package to succeed.
> > 
> > I'm now back to max_loop set to 32 :(
> 
> In case of use_lvmetad = 0, the effective filter is "devices/filter"; while
> in case of use_lvmetad = 1, the effective filter is "devices/global_filter".
> Please see the comment about this:
> 
>     # Since "filter" is often overridden from command line, it is not
> suitable
>     # for system-wide device filtering (udev rules, lvmetad). To hide devices
>     # from LVM-specific udev processing and/or from lvmetad, you need to set
>     # global_filter. The syntax is the same as for normal "filter"
>     # above. Devices that fail the global_filter are not even opened by LVM.
> 
>     # global_filter = []
> 
> So in your case you need to add this to your lvm.conf.
>     global_filter = ["r|/dev/loop.*|", "a/.*/"]

Yes, you're right, I should have read that before. To have a similar setup for
the case lvmetad get's disabled again somehow, I also added "r|/dev/loop.*|" to
"devices/filter".

But, while we're at comments... The comment for "global/raid10_segtype_default"
says for the possible setting "mirror":

    # "mirror" - LVM will layer the 'mirror' and 'stripe' segment types.  It
    #            will do this by creating a mirror on top of striped sub-LVs;
    #            effectively creating a RAID 0+1 array.  This is suboptimal
    #            in terms of providing redunancy and performance.  Changing to
    #            this setting is not advised.

To me this sounds like the default should not be set to "mirror", however it is
actually. Shouldn't it be set do "raid10"? FWIW, I have now changed that
setting to read "raid10".