beautypg.com

Server shadowing and recovery b.9 server states, Figure b–2 server states – Compaq AA-Q88CE-TE User Manual

Page 271

background image

Server Shadowing and Recovery

B.9 Server States

Figure B–2 Server States

WAIT−TR−OK

WAIT−TR−RETRY

Retry

Router detects

definition clash

Propose KR
to Routers

Error

Proposal accepted
− commit KR

ACTIVE

REMEMBER

CATCHUP

WAIT
CATCHUP

SECONDARY

WAIT−JNL

WAIT RESTART

RESTART

Router sends
list of recovery
Journals

STANDBY

SECONDARY
STANDBY

KR already

active on

another CPU

Secondary
already active

in cluster

Primary site
failure

Primary node
failure

Inaccessible
Journal

Journal
becomes
accessible

RECOVERING

WAIT−RVY

Inaccessible
Journal

Journal
becomes
accessible

Primary
active

No Primary

No Secondary

Journal recovery
data found (if any)

Journal recovery
data found (if any)

Inaccessible
Journal

Journal
becomes
accessible

Primary
active

Secondary is
ready

Primary
failure

Secondary
node failure

Legend:
KR Key range
TX Transaction
TR TX Router

CDS 8−NOV−1991 17:23:35

Non−shadowed
Primary

Server declaration
rejected

DD

INITIAL

WAIT_QUORUM

Propose KR
to Routers

Backend not
yet quorate

Server Shadowing and Recovery B–7