TOPIC:

i cannot reinstall xen now.

but i tryed to recreate SR with new IQN, but result is still the same.
also first host with applyed filter work fine.

before changing roles(without filter on DRBD device) both hosts work fine.
and second one cannot use DRBD device because it was secondary DRBD device.

may be i need to try fully clean DRBD device storage if it will do anything usefull?

You should not have to reinstall xenserver.. I suggest the following steps:

- remove the iscsi SR from xenserver
- shutdown tgtd, drbd, ha-lizard, ha-lizard-watchdog, iscsi-ha, iscsi-ha-watchdog (make sure to shutdown the watchdogs first)
- make sure your LVM filter is set the same on both hosts. Delete the LVM cache and then vgscan
- make sure the TGT target is identical on both hosts. IQN, LUN, Serial MUST be the same. Also ensure the TGT target is using the DRBD device and not the backing disk

With everything verified - "service iscsi-ha start -w" and "service ha-lizard start -w"

nothing changed.