Rotating snapshots with Solutions Enabler.

I thought I'd update with progress so far - I think I've managed to pull together a solution.

Unfortunately I was barking up the wrong tree initially.

But what I've done now, is - using XML::Twig - pull together a script that picks out the sessions listed in a symsnap query -multi -XML

Process it, recreate the 'oldest' VDEVs, and then activate them (consistently).

I've not posted the detail of how that's done here, as it's ... rather verbose perl.

If anyone's interested, I'll do so though.

It goes a bit like this:

You'll need the library XML::Twig - which you'll be able to get from CPAN.

This subroutine populates a hash called '%devices' such that you can refer to:

keys ( %devices ) to get a list of all the logical device ids in your device group.

$devices{$LDEV}{'newest'} to get the newest snap

$devices{$LDEV}{'oldest'} to get the oldest snap.

And @{ $device{$LDEV{'all'} } to get all the device IDs with snaps - again, in order.

I've omitted how to actually do the snap recreate and activate, as it shouldn't be too hard to figure out.

You'll have to handle setting $device_group yourself as well.

(Oh, and you might need to omit the -rdf. This works on a remote VDEV)

sub session_twig_parser

{

  #this is called each time the parser hits the element tag 'session' in the doodad.

  #It DOESN'T differentiate between snaps or clones - they're all 'sessions'.

  #but this should be handled by the fact you ran 'symsnap query'.

  my ( $twig, $session ) = @_;

  my $state = $session -> first_child_text('state');

  my $SRC_DEV_LD = $session -> first_child('Source') -> first_child('ld_name') -> text;

  my $TGT_DEV_LD = $session -> first_child('Target') -> first_child('ld_name') -> text;

  my $SRC_DEV_name =  $session -> first_child('Source') -> first_child_text('dev_name');

  my $TGT_DEV_name =  $session -> first_child('Target') -> first_child_text('dev_name');

    if ( $devices{$SRC_DEV_LD} )

    {

      #it already exists, so we have already 'seen' the newest LUN.

      push ( @{ $devices{$SRC_DEV_LD}{'all'} }, $TGT_DEV_LD );

      #we overwrite the 'oldest' LUN, because this one will be older than any we've seen already.

      $devices{$SRC_DEV_LD}{'oldest'} = $TGT_DEV_LD;

      $devices{$SRC_DEV_LD}{'oldest_state'} = $state;

    }

    else

    {

      #we haven't seen this SRC LD before, so we can assume that the TGT we see is the 'newest'.

      $devices{$SRC_DEV_LD}{'newest'} = $TGT_DEV_LD;

      #populate a list, 'all' which has all the devices in this 'set' in chronological order.

      #Not used in this script, but will let you do things like figure out

      #which snaps were taken at the same time, for doing a recovery of multiple LUNs.

               push ( @{ $devices{$SRC_DEV_LD}{'all'} }, $TGT_DEV_LD );

      #we also store this device as 'oldest' because if there's only one, it's both.

      $devices{$SRC_DEV_LD}{'oldest'} = $TGT_DEV_LD;

      $devices{$SRC_DEV_LD}{'oldest_state'} = $state;

    }

}

my $output = `$symcli_path/symsnap -g $device_group query -rdf -multi -output xml`;

#we set up this twig to process any occurance of XML tag 'Session' in the subroutine 'session_twig_parser'.

my $twig = new XML::Twig (

             twig_handlers => { 'Session' => \&session_twig_parser }

          );

$twig -> parse ( $output );

HI,

Would appreciate if you can share with me the scripts that you have created.

Thank you.