To calculate the shredding time for a volume, multiply the shredding time for the drives by the volume capacity in TB, and then multiply that value by the number of overwrite passes:
shredding-time-for-a-volume = shredding-time-for-drives × volume-capacity-in-TB × number-of-overwrite-passes
Example: 60-TB NVMe SSDs (TLC), 40-TB volume, 3 overwrite passes (default):
(5 minutes/TB × 40 TB) × 3 = 200 minutes
- The standard shredding time for encrypted and unencrypted parity groups is the same.
- When host I/Os are being performed, the required shredding time is at least 6 times longer than when no host I/Os are performed.
- The shredding time for NVMe SSDs might be a quarter or less of the expected time, depending on the internal state of the SSD.
- The number of LDEVs subject to shredding is the maximum number of LDEVs when assuming that the capacity per LDEV is 100 GB in the capacity of 1 TB in a parity group or a pool. The standard shredding time is the time required for shredding all LDEVs subject to shredding.
- If there is a heavy I/O load on a parity group (including parity groups not being shredded), the shredding operation might fail. If a failure occurs, reduce the I/O load, and then perform the shredding operation again.
The following tables list the shredding times for drives in a single parity group.
|
RAID level |
Standard shredding time (minutes) |
|||
|---|---|---|---|---|
|
VSP One B24 |
VSP One B26 |
VSP One B28 |
||
|
RAID 5 |
3D+1P |
100 |
25 |
37.5 |
|
RAID 6 |
6D+2P |
50 |
12.5 |
25 |
|
14D+2P |
25 |
12.5 |
12.5 |
|
|
RAID level |
Standard shredding time (minutes) |
|||
|---|---|---|---|---|
|
VSP One B24 |
VSP One B26 |
VSP One B28 |
||
|
RAID 5 |
3D+1P |
100 |
25 |
37.5 |
|
RAID 6 |
6D+2P |
50 |
12.5 |
25 |
|
14D+2P |
25 |
12.5 |
12.5 |
|
|
RAID level |
Standard shredding time (minutes) |
||
|---|---|---|---|
|
VSP One B26 |
VSP One B28 |
||
|
RAID 5 |
3D+1P |
25 |
37.5 |
|
RAID 6 |
6D+2P |
12.5 |
25 |
|
14D+2P |
12.5 |
12.5 |
|
|
RAID level |
Standard shredding time (minutes) |
||
|---|---|---|---|
|
VSP One B24 |
VSP One B26 / VSP One B28 |
||
|
RAID 5 |
3D+1P |
10 |
55 |
|
RAID 6 |
6D+2P |
5 |
5 |
|
14D+2P |
5 |
5 |
|
|
RAID level |
Standard shredding time (minutes) |
||
|---|---|---|---|
|
VSP One B24 |
VSP One B26 / VSP One B28 |
||
|
RAID 5 |
3D+1P |
10 |
5 |
|
RAID 6 |
6D+2P |
5 |
5 |
|
14D+2P |
5 |
5 |
|
|
RAID level |
Standard shredding time (minutes) |
||
|---|---|---|---|
|
VSP One B24 |
VSP One B26 / VSP One B28 |
||
|
RAID 5 |
3D+1P |
10 |
5 |
|
RAID 6 |
6D+2P |
5 |
5 |
|
14D+2P |
5 |
5 |
|
|
RAID level |
Standard shredding time (minutes) |
||
|---|---|---|---|
|
VSP One B24 |
VSP One B26 / VSP One B28 |
||
|
RAID 5 |
3D+1P |
15 |
5 |
|
RAID 6 |
6D+2P |
5 |
5 |
|
14D+2P |
5 |
5 |
|
|
RAID level |
Standard shredding time (minutes) |
|
|---|---|---|
|
VSP One B26 / VSP One B28 |
||
|
RAID 5 |
3D+1P |
5 |
|
RAID 6 |
6D+2P |
5 |
|
14D+2P |
5 |
|
|
RAID level |
Standard shredding time (minutes) |
|
|---|---|---|
|
VSP One B26 / VSP One B28 |
||
|
RAID 5 |
3D+1P |
5 |
|
RAID 6 |
6D+2P |
5 |
|
14D+2P |
5 |
|