IBM FlashSystem 840 Product Guide
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FlashSystem 840 supports the RAID 5 configurations with the latest capacity points with the addition of 1
TB modules listed in Table 7.
Table 7. Supported FlashSystem RAID 5 configurations with latest FlashSystem 840 capacity points
Capacity Selection (in TB)
FlashSystem 840 initial release FlashSystem 840 current release
2
4 X 1 TB
4
4 X 2TB
6 X 1 TB
6
8 X 1 TB
8
4 X 4 TB
10 X 1 TB
10
12 X 1 TB
12
8 X 2 TB
8 X 2 TB
16
10 X 2 TB
20
12 X 2 TB
12 X 2 TB
24
8 X 4 TB
8 X 4 TB
32
10 X 4 TB
40
12 X 4 TB
12 X 4 TB
RAID 5 configurations provide a high degree of redundancy with Variable Stripe RAID as well as a RAID 5
protection. RAID 5 data protection includes two flash modules dedicated as parity and hot spare.
Small or large RAID 5 configurations
The cost of using RAID 5 as compared to RAID 0 is capacity. A RAID 5 configuration uses one flash
module as parity and one flash module as spare. Maximum capacity utilization for RAID 5 is provided
using 12 flash modules.
Depending on client needs, and if capacity expansion is expected over time, clients may consider initial
RAID 5 configurations with 12 flash modules which provides the least capacity penalty for RAID 5
protection. In comparison small configurations using only four flash modules configured in RAID 5 cost
half of the total capacity reserved for redundancy.
Note: Different flash module sizes cannot be intermixed in the same IBM FlashSystem 840 chassis.
