mirror of
https://github.com/schoebel/mars
synced 2024-12-27 17:12:32 +00:00
179 lines
9.0 KiB
Plaintext
179 lines
9.0 KiB
Plaintext
===================================== CLUSTER ======================================================================
|
|
|
|
action pre-conditions post-conditions
|
|
================ ================================================== =============================================
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
1. create no cluster present cluster created
|
|
mars module not inserted /mars mounted
|
|
/mars mounted
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
2. join (1.) on primary host cluster joined
|
|
cluster not joined /mars mounted
|
|
mars module not inserted
|
|
/mars mounted
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
3. leave (1.) or (2.) no cluster present
|
|
no resources existent
|
|
|
|
|
|
===================================== RESOURCE =====================================================================
|
|
|
|
The state of a resource comprises the states of 3 objects (role, disk, replication) taking the following values:
|
|
|
|
role: primary secondary
|
|
----
|
|
|
|
disk:
|
|
----
|
|
detached : underlying device may be used by other applications
|
|
outdated : role = secondary
|
|
AND consistent
|
|
AND [ not all logfiles have been fetched from the primary
|
|
OR primary_unreachable ]
|
|
uptodate : consistent
|
|
AND [ role = primary OR [ role = secondary
|
|
AND no logfiles are to be fetched
|
|
AND repl != primary_unreachable] ]
|
|
inconsistent: none of the three states above (a sync, restore or similar action is necessary
|
|
to reach a consistent state)
|
|
|
|
repl:
|
|
----
|
|
notjoined : role = secondary AND resource exists on the primary only
|
|
replaying : consistent disk
|
|
AND [ [ role = primary AND can "send" logfiles ]
|
|
OR [ role = secondary AND can receive logfiles ] ]
|
|
primary_unreachable : what the name means
|
|
paused_sync : interrupted while syncing
|
|
syncing : what the name means
|
|
paused_replay : able to replay, but interrupted
|
|
disconnected : not used until now, probably not necessary
|
|
|
|
For data consistence the states of the following objects are important too:
|
|
|
|
device (the "underlying" device):
|
|
------
|
|
locked : cannot be opened by other applications
|
|
unlocked: usable as a normal block device by other applications
|
|
unused : not used by any application
|
|
|
|
mars_device:
|
|
-----------
|
|
usable : can be used in "normal" ways
|
|
invisible: what the name means
|
|
undef : not existent
|
|
|
|
===========
|
|
Hint: Of course the states are not independent, e.g.:
|
|
|
|
disk != detached => device = locked
|
|
repl = synching && role = secondary => disk inconsistent
|
|
|
|
These action independent rules will not be regarded here and must be guaranteed by tests.
|
|
===========
|
|
|
|
In the following table the states which are of no interest in the specific
|
|
action are omitted or their values are marked with *.
|
|
The disk state "consistent" is an abreviation for outdated || uptodate
|
|
|
|
|
|
action pre-conditions post-conditions
|
|
============= ================================================== =================================================
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
4. create
|
|
(1.)
|
|
mars module inserted role : primary
|
|
device: unused disk : uptodate
|
|
repl : replaying
|
|
mars_device : usable
|
|
device : locked
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
5. join
|
|
(4.) on primary host, (2.) role : secondary
|
|
mars module inserted disk : uptodate
|
|
repl : notjoined repl : replaying
|
|
device : unused mars_device : invisible
|
|
device : locked
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
6. leave
|
|
(4.) or (5.) disk : detached
|
|
disk: uptodate mars_device : undef
|
|
outdated device : unlocked
|
|
-> wait | force
|
|
repl: disconnected
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
7. switch primary -> secondary
|
|
(4.) or (5.) role : secondary
|
|
role : primary disk : uptodate
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
8. switch secondary -> primary
|
|
(4.) or (5.) role: primary
|
|
no other primary host (evtl. locking (two mounts!))
|
|
role : secondary
|
|
disk : uptodate
|
|
outdated
|
|
-> wait | force
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
9. pause_sync
|
|
(4.) or (5.) repl: paused_sync
|
|
repl: synching
|
|
!synching
|
|
-> hint
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
10. pause_replay
|
|
(4.) or (5.) repl: paused_replay
|
|
repl: replaying
|
|
!replaying
|
|
-> hint
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
11. invalidate
|
|
(4.) or (5.) disk: inconsistent
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
12. logrotate
|
|
(4.) or (5.) log rotated
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
13. logdelete
|
|
(4.) or (5.) log deleted
|
|
logfile closed
|
|
AND logfile received from all secondaries
|
|
|
|
|
|
|
|
===================================== DEVICES ======================================================================
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
14. attach
|
|
(4.) or (5.) disk: if no "out of mars changes" occured since detach
|
|
disk: detached state = state before detach
|
|
else
|
|
state = inconsistent
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
15. detach
|
|
(4.) or (5.) disk: detached
|
|
|
|
|
|
--------------------------------------------------------------------------------------------------------------------
|
|
|
|
===================================== FURTHER INFOS NEEDED =========================================================
|
|
|
|
1. all state infos from remote hosts are to be provided with a timestamp indicating their actuality
|
|
|
|
2. replication states like synching, replaying need a "progress bar"
|
|
|
|
3. useless actions (e.g. primary on a resource beeing already primary) should be handled as tolerant as possible
|
|
|