Ibm Totalstorage Ds400 Disk Subsystem - IBM TotalStorage DS300 Best Practices Manual

The DS300 failover mode can be set only with the CLI using the following
command:
controller ipfailover <mode>
The default failover mode is remote.
Important: Use of the both failover mode is not recommended because it
would require routing interfaces.

3.4 IBM TotalStorage DS400 disk subsystem

Unlike the DS300, the IBM TotalStorage DS400 storage subsystem offers 2 Gbps
Fibre Channel (FC) host fabric ports per controller and can therefore be
connected to Fibre Channel switches.
Up to 14 ultra 320 drives are supported in a DS400. A total of 40 ultra 320 drives
can be archived by attaching up to two EXP400 enclosures. Each EXP400
enclosure can hold up to 13 drives.
The number of drives in an array depends on the RAID level chosen to be used.
For RAID 0, 1 and 5 arrays up to 16 drives can be used to build a logical drive.
With a RAID level 10 or 50 up to 40 drives are possible.
The DS400 supports asynchronous logical unit access (ALUA), which means
that only one controller at a time can access the physical disk drives. This is often
referred to as active/passive configuration.
The DS400 storage subsystem is available on two models as shown in Table 3-6.
Table 3-6 DS400 models
Fibre channel RAID controller
Controller upgrade
Controller system memory
RAID cache (per controller)
Write cache enabled
Battery backup for cache
Flashcopy copy services
1700-1RS
1
Yes
512MB, 1GB max
256MB
Yes
Yes
256 Flashcopy target logical
drives with 1GB system memory
1700-2RD
2
N/A
512MB, 1GB max
256MB
No
Yes
256 Flashcopy target logical
drives with 1GB system memory
Chapter 3. Components overview
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