HP XP Continuous Access Software - Manual (Page 40)

40 Continuous Access XP for the XP1024/XP128
S-VOL using the S-VOL’s LDEV ID in the host command. The BC remote console software displays the
LDEV ID and BC pair status of all S-VOLs associated with a P-VOL.
Figure 15 through Figure 18 show various Continuous Access XP/BC configurations that share volumes.
Continuous Access XP supports synchronous and asynchronous operations for shared Continuous Access
XP/BC volumes.
• Figure 15 shows an example of a Continuous Access XP P-VOL that also functions as a BC P-VOL.
With this configuration, use BC for on-site data backup if a Continuous Access XP failure occurs, and
use Continuous Access XP to provide remote backup of the BC P-VOL if a BC failure occurs.
Figure 15 Shared Continuous Access XP P-VOL and shared BC P-VOL
• Figure 16 shows an example of a Continuous Access XP S-VOL that also functions as a BC P-VOL.
With this configuration, use BC to provide multiple backup copies of a single Continuous Access XP
P-VOL.
Figure 16 Shared Continuous Access XP S-VOL and shared BC P-VOL
Table 10 Host pair status reporting for Continuous Access XP, BC, and Continuous Access XP/BC
shared volumes
Number of Continuous
Access XP pairs
Number of BC
S-VOLs
Pair status reported by disk array
0 0 Simplex
0 1 BC pair status
0 2 or more BC pair status for pair whose S-VOL has lowest LDEV ID
1 0 Continuous Access XP pair status
1 1 Continuous Access XP pair status
1 2 or more Continuous Access XP pair status
Table 11 Data currency of a shared Continuous Access XP/BC volume
Continuous
Access XP pair
status
BC pair status
COPY (PD)
PAIR COPY (SP) PSUS COPY (RS/RS-R) PSUE
COPY Not current Not current Not current CURRENT Not current Not current
PAIR Not current Not current Not current CURRENT Not current Not current
PSUS/PSUE Not current CURRENT CURRENT CURRENT CURRENT Not current