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Copy-back and copy-back-less operation

After the failed dis kas been replaced with a new disk, data on the hot-spare disk is retrieved (copied back) to the new disk. The copy-back function restores the RAID group while maintaining redundancy after the rebuild has been performed for the hot-spare in the RAID group.

copy-back figure

Copy-back-less function is a feature which builds hot-spare disks into a RAID configuration after the completion of rebuild or redundant copy and the internal RAID configuration of the failed disk is changed to hot-spare disk. Immediately after maintenance and replacement, it can start working as a hot-spare disk. This feature means that the copy-back process is no longer required.
Note: Copy-back-less function is featured by ETERNUS DX S3 series and ETERNUS DX200F only.

coppy-back-less figure


Example:

Rebuild: 4 hours, copy-back: 4 hours, disk replacement: 0.5 hours
Working time for replacement of disk Time until HS becomes available
Copy-back Max 8.5 hours
(Rebuild + Replacing Disk + Copyback)
8.5 hours
(Rebuild + Replacing Disk + Copyback)
Copy-back-less Max 4.5 hours
(Rebuild + Replacing Disk)
4.5 hours
(Rebuild + Replacing Disk)

The administrator can choose between copy-back and copy-back-less operation via the GUI. (Only for ETERNUS DX S3 series and ETERNUS DX200F.)

Benefit

  • Disk replacement time is drastically reduced
  • RAID availability is improved as the hot-spare dontime is reduced
  • I/O performance degradation during the copy-back process can be avoided

Product Requirements

Supported Storage Disk Storage Systems ETERNUS DX60 S3
ETERNUS DX100 S3/DX200 S3
ETERNUS DX500 S3/DX600 S3
ETERNUS DX8700 S3/DX8900 S3
ETERNUS DX60/DX60 S2
ETRENUS DX80/DX80 S2
ETERNUS DX90/DX90 S2
ETERNUS DX400/DX400 S2 series
ETERNUS DX8000 series/DX8700 S2
ETERNUS2000/ETERNUS4000/ETERNUS8000
All Flash Arrays ETERNUS DX200F