Coffer Disk

Built-in Coffer Disk

Each controller houses one or more disks as coffer disks. Table 4-91 describes capacity partitions of the built-in coffer disks.

External Coffer Disk

The first four disks in the storage system are configured as coffer disks. SAS, NL-SAS, and SSD disks can be used as coffer disks. The type of the four coffer disks must be the same.

Appearance

Figure 4-212, Figure 4-213, and Figure 4-214 show the appearances of coffer disks.

Figure 4-212 2.5-inch coffer disk

Figure 4-213 3.5-inch coffer disk

Figure 4-214 Palm-sized NVMe SSD as a coffer disk

Positions

• If a storage system employs the disk and controller integration architecture, the first four disks in the storage system are configured as coffer disks. Figure 4-215 uses a 2 U controller enclosure with 25 disk slots as an example.
  Figure 4-215 Positions of external coffer disks in the disk and controller integration architecture
  

• If a storage system employs the disk and controller separation architecture, the first four disks in the first disk enclosure are planned as coffer disks. Figure 4-216 uses a 2 U disk enclosure with 25 disk slots as an example.
  Figure 4-216 Positions of external coffer disks in the disk and controller separation architecture
  

Capacity partitions

• For the disk and controller integration device, the first four disks each spares 6 GB of space to form a RAID 1 group. The rest of the coffer disk space can be used to store service data. Table 4-92 describes capacity partitions of external coffer disks.
  Table 4-92 Capacity partitions of external coffer disks

  Partition Name	Partition Size	Description
  CCDB partition	3 GB	Stores the user configuration information (such as remote replication, HyperMetro, and NAS data). The four coffer disks are mirrors of each other for redundancy.
  LogZone partition	2 GB	Stores system logs and run logs when the storage system is powered off and write through is enabled. The four coffer disks are mirrors of each other for redundancy.
  DB partition	1 GB	Stores the user configuration information (such as information about the LUN capacity, ID, WWN, Fibre Channel ports, and iSCSI ports). The four coffer disks are mirrors of each other for redundancy.

• For the disk and controller separation device, the first four disks each spares 7 GB of space to form a RAID 1 group. The rest of the coffer disk space can be used to store service data. Table 4-93 describes capacity partitions of external coffer disks.
  Table 4-93 Capacity partitions of external coffer disks

  Partition Name	Partition Size	Description
  CCDB partition	2 GB	Stores the user configuration information (such as remote replication, HyperMetro, and NAS data). The four coffer disks are mirrors of each other for redundancy.
  LogZone partition	4 GB	Stores system logs and run logs when the storage system is powered off and write through is enabled. The four coffer disks are mirrors of each other for redundancy.
  DB partition	1 GB	Stores the user configuration information (such as information about the LUN capacity, ID, WWN, Fibre Channel ports, and iSCSI ports). The four coffer disks are mirrors of each other for redundancy.