The suspending and deleting states are temporary internal states within the
RAID storage system. CCI cannot detect these transition states, because
these states are reported on the previous state of the storage system. These
states are therefore concealed inside the pairsplit command. After the
pairsplit command is accepted, host write I/Os for the P-VOL are managed
by the cylinder bitmap (normal), non-transmitted data remaining in the P-
VOL's FIFO queue is transferred to the S-VOL's FIFO queue, and the pair
status is then set to PSUS [SMPL] state when all data in the P-VOL's FIFO
queue has been transmitted.
PFUL. If the quantity of data in sidefile cache exceeds 30% of cache storage,
the internal status of the RAID storage system is PFUL, and host write I/Os
receive delayed response in the range of 0.5 seconds (minimum) to 4
seconds (maximum).
PFUS. If the quantity of data in sidefile cache exceeds the user-defined
sidefile area (30%-70%), then host write I/Os must wait for enough sidefile
space to become available for storing the next new write data. If a copy
pending timeout occurs during this waiting state, then the pair status
changes from PAIR to PFUS, host write I/Os are accepted, and write data is
managed by bitmap.
The CCI software can detect and report the PFUL and PFUS states as follows:
• As a return code of the pairvolchk command
• As the status code displayed to code item by the pairmon command
• As the paired status displayed to status item using -fc option of
pairdisplay command
Table 6-8 State table for TrueCopy vs. TrueCopy Async
CCI
state
Storage
system
internal
state
Description
Writing control on TC
async volume
Transfer
data via
ESCON
TrueCopy
Sync
TrueCopy Async
Writing
data
Response
SMPL SMPL SMPL Same Normal Usual None
COPY COPY COPY Same Via Sidefile Usual* Sidefile
& bitmap
Deleting N/A Deleting from COPY using
[pairsplit -S]
Normal Usual Sidefile
Suspending N/A Suspending from COPY by
using [pairsplit]
Via Bitmap Usual Sidefile
PAIR PAIR Synchronized Async
sidefile in
use
Less than HWM Via Sidefile Usual Sidefile
PFUL N/A HWM to
Threshold
Via Sidefile Delayed Sidefile
Over
Threshold
Via Sidefile Wait until
under
threshold
Sidefile
6-28
Data replication operations with CCI
Command Control Interface User and Reference Guide
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