The standard required time for shredding (without host I/Os) differs depending on the drive type. For details, see the following sections.
- Standard required time for hard disk drives
- Standard required time for SSDs (with SAS interface)
- Standard required time for SSDs (with NVMe interface)
- Standard required time for SCMs
- Standard required time for FMDs
In these sections, the tables assume the use of OPEN-V volumes with drive type DKxxx-JxxxSS/KxxxSS/HxxxSS. The same standard times also apply to shredding encrypted drives.
Since each volume is overwritten three times with dummy data by default, Volume Shredder requires three times the time listed in the tables. If the number of overwrites has been changed, use the following formula to calculate the time required for shredding:
(time required for shredding) = [time for one overwrite (standard required time)] x (number of overwrites (n))
When host I/Os are performed, the required shredding time is at least six times that of when no host I/Os are performed. If a DKxxx-HxxxSS data drive is used for creating a parity group on an encrypted data drive, the time required for shredding that parity group is the maximum time listed.
Notes on shredding times
- In these sections, the tables also assume the following conditions:
- For VSP 5000 series, 8 DKBs/DKBNs are mounted per system. For VSP G/F700 and VSP G/F900, 2 DKBs are mounted per cluster.
- Shredding is performed on one ECC group.
- The assumed number of LDEVs is the maximum number of LDEVs that is allowed per ECC group when each LDEV has 100 GB of capacity. If each LDEV does not have 100 GB of capacity, the required time might be longer than the time in the tables.
- If the volumes to be shredded belong to drives of mixed types or mixed configurations, the longest required times associated with the drive type or drive configuration apply to all volumes. Thus, mixed types and configurations take more time for the volumes to become available for use than when the drive type and drive configuration are the same. When you add drives or change drive configurations, you should arrange the drives into those with the same standard required times, and then add drives starting with those volume types requiring the least shredding time.
- When the emulation type for mainframe is selected for the LDEV, Fibre Channel connectivity for mainframe is required. When the emulation type for open systems is selected, a channel for open systems is required.
- Complete data erasure can be guaranteed only for disk drives. For information about complete data erasure for flash drives and SCMs, contact customer support.