Hitachi TrueCopy for IBM z/OS User and Reference Guide (T5211-96001, June 2007)

About TrueCopy for z/OS Operations 2-25
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
Table 2-4 Sidefile Thresholds
Operation Threshold(s) Action(s)
TCzA High-water mark (HWM) = sidefile threshold –
20%
MCU (RCU) reaches HWM: command retry to
host (MCU), begin graduated delay. Delay times
can be adjusted using mode 93 (see Table 2-2).
Sidefile threshold = 30-70% of cache, default =
50%.
TCzA threshold can be adjusted from 30-70% (in
10% increments) using the TCz software.
MCU (RCU) reaches threshold: command retry
to host (MCU), max delay time (500 or 100
ms). Delay time can be adjusted using mode 93
(see Table 2-2).
Puncture threshold = sidefile threshold + 10% MCU (RCU) reaches puncture: suspend
affected TCzA pairs due to sidefile overflow
condition.
CC
[CC sidefile] / [avail cache] = 40%, 50%, 60%
CC thresholds can be adjusted by using modes 85
and 86 (see Table 2-2).
Threshold 1/2/3 = 30/40/50%, 40/50/60%, or
60/70/80%
Threshold 1 = no action.
Threshold 2 = SCP message.
Threshold 3 = puncture condition.
Write Pending [write pending] / [avail cache - sidefile] = 70% Command retry.