Fujitsu ETERNUS DX60 S3 - Basic Size When Stripe Depth Is Tuned (for TPP Capacity)

Appendix F Basic Size and MWC Input Condition for RAID Groups
F.1 Basic Size for each RAID Group
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*1: D: Data drives, M: Mirror drives, P: Parity drives
*2: Basic size when creating volumes.
The ETERNUS DX manages volumes in units of stripe size. If the volume size is not an exact multiple of the basic size
(stripe size), then when a RAID group is created the remainder at the end of the last stripe used will be lost. Stripe
size is independent of the disk drive capacity. Figure F.1
shows what happens when the volume size is an integral
multiple of the basic size and what happens when it is not.
F.1.5 Basic Size When Stripe Depth is Tuned (For TPP Capacity)
When Stripe Depth is tuned for RAID groups that are used as TPPs, the basic size that can be used for the TPPs
may increase. The following table shows RAID group configurations in which the basic size is different from
the normal size.
High Capacity
(RAID5)
8D+1P 2 x Number of
concatenations
2 x Number of
concatenations
––
9D+1P 9 x Number of
concatenations
–––
10D+1P 5 x Number of
concatenations
–––
11D+1P 11 x Number of
concatenations
–––
12D+1P 3 x Number of
concatenations
–––
13D+1P 13 x Number of
concatenations
–––
14D+1P 7 x Number of
concatenations
–––
15D+1P 15 x Number of
concatenations
–––
RAID level Drive
configuration
(*1)
Basic size (MB)
(Lowest exact MB multiple) (*2)
When the Stripe Depth is ...
128KB 256KB 512KB 1024KB
Basic size Stripe Depth RAID group configuration
42 MB
256 KB RAID1+0 (8+8)
512 KB RAID0 (4D), RAID1+0 (4+4), RAID1+0 (12+12)
84 MB
512 KB RAID1+0 (8+8), RAID1+0 (12+12)
1024 KB RAID0 (4D), RAID1+0 (4+4), RAID1+0 (12+12)
168 MB 1024 KB RAID1+0 (8+8)
If the TPP capacity is not an exact multiple of the basic size, areas that cannot be used as TPPs are created in
the RAID group.