Re: [AUTOREBUILD 0/8] Autorebuild monitor patches based on user defined policy

[Neil Brown <neilb@suse.de>]

On Fri, 1 Oct 2010 13:36:48 +0100
"Labun, Marcin" <Marcin.Labun@intel.com> wrote:

> >From f423b226f10cfe3b416c5e0580dde45cd8ca887d Mon Sep 17 00:00:00 2001
> From: Marcin Labun <marcin.labun@intel.com>
> Date: Wed, 29 Sep 2010 06:12:38 +0200
> Subject: [AUTOREBUILD 0/8] Autorebuild monitor patches based on user defined policy
> 
> This is updated series of patches forming autorebuild functionality in mdadm 
> monitor based on new policy code.

Hi Marcin,
 thanks for this, and apologies for not replying sooner.
 I've had a bit of a look and some of it seems good.
 I haven't had a thorough look yet as I am in the middle of doing some fairly
 serious refactoring of mdadm (the supertype, and mdinfo structures are going
 to be heavily changed and largely merged - some super_switch methods will
 disappear (e.g. getinfo_super) and others will appear (load_container)).
 Once I have finished that I will review your code more thoroughly and merge
 it into the new code base.

 One concern I do have is patch 0002 which removes the spare-group based
 spare migration.  That functionality needs to stay, though obviously the
 implementation can change.  I imagine the 'spare-group' information would be
 added to each member device as a 'domain' name.

 Also it is best not to remove functionality and then re-add it a different
 way, but rather to make sure the functionality works after every change, but
 just gets extended at various points.

Thanks,
NeilBrown


> 
> Autorebuild Monitoring application:
> Autorebuild monitor is part of monitor application (mdadm -F). In the current
> code of mdadm monitor autorebuild feature was based on spare group assignment in
> mdadm.conf file and worked only for native metadata. 
> The new autorebuild implementation works for all metadata types. It uses 
> the concept of domains in mdadm.conf introduced by Neil Brown. 
> Monitoring application shall periodically check the state of MD active arrays
> and trigger a rebuild if there are eligible spare disks in other containers.
> Degraded arrays are checked one by one. For each array a potential spare disk
> is searched. If the spare disk matches the domain of the degraded array and
> the domain action allows for spare sharing the spare is moved using existing
> Manage_subdevs function. If the addition fails, the spare device is moved back
> to the original container and next potential spare is tried. The process is 
> repeated until all arrays are checked and the process is put into a sleep state
> for a configured period.
> 
> The design of mdadm monitor requires that there is only one autorebuild process running.
> Therefore a new option -no-sharing has been added to Monitor mode, and spare sharing is
> allowed in only one instance of Monitor. User is still able to start Monitoring functions
> in multiple instances.
> 
> The autorebuild build-in assumptions are:
> 1\spares are shared between the arrays of the same metadata
> 2\spares are moved only from containers/volumes that are not degraded
> 3\spares are moved to containers/volumes lacking a *good* spare (size)
> 
> 
> 0001-Monitor-set-err-on-arrays-not-in-mdstat.patch
> 0002-Monitor-removed-spare-group-based-spare-sharing-code.patch
> 0003-mdadm-added-no-sharing-parameter-for-Monitor-mode.patch
> 0004-Monitor-link-container-volumes-in-statelist.patch
> 0005-imsm-create-mdinfo-list-of-disks-in-a-container-from.patch
> 0006-Monitor-autorebuild-funcionality-added.patch
> 0007-Monitor-Respect-policy-in-auto-rebuild-in-mdadm-moni.patch
> 0008-Monitor-Helper-functions-added-for-spare_sharing-in-.patch
> 
> 
>  Monitor.c     |  605 +++++++++++++++++++++++++++++++++++++++++++++++----------
>  ReadMe.c      |    2 +
>  mdadm.c       |    8 +-
>  mdadm.h       |    8 +-
>  super-intel.c |   53 +++++
>  5 files changed, 565 insertions(+), 111 deletions(-)
>