Huawei OceanStor 2000 V3 Series - Page 35

are deactivated. The remote storage array provides services for hosts. In addition to
ensuring robust reliability and service continuity, HyperMetro also improves resource
utilization of storage arrays.
Write I/O Process
Figure 1-3 shows the write I/O process (write back as an example) when a host sends an I/O
request and gives rise to data changes in scenarios where services are running properly.
Figure 1-3 Write I/O process
LOG
2
8
4
8
DCL
5
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Local storage array Remote storage array
Host
Same-city data
center network
IP/FC
Storage
Host cluster
Local
cache
Disk
Remote
file system
Local file
system
4 5
Remote
cache
Disk
LOG
HyperMetro management module
3
6
3 6
1. A host delivers a write I/O to the HyperMetro management module.
2. A log is recorded in the local storage array.
3. The HyperMetro management module writes the write I/O to both the local and remote
file systems concurrently.
4. The local file system writes the write I/O to local cache and the remote file system writes
the write I/O to remote cache.
5. The local cache returns the write I/O result to the local file system and the remote cache
returns the write I/O result to the remote file system.
6. The local and remote file systems return the write I/O results to the HyperMetro
management module.
7. The storage system determines whether dual-write is successful.
– If the write I/O request is processed successfully, the log is deleted.
– If the write I/O fails to be written to the local or remote cache, the log is converted
into a DCL. The DCL records the differential data between the local and remote file
systems.
OceanStor V3 Series
HyperMetro Feature Guide for File
1 Feature Description
Issue 05 (2018-01-30) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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