IBM ServeRAID-4 Ultra160 Series, Справочник пользователя

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ServeRAID considerations
It is important to understand the following ServeRAID considerations before you set
up your high-availability cluster solution.
Note: The following ServeRAID considerations are for the Microsoft Cluster
Solution using Windows NT and Windows 2000. For similar considerations
for the Novell IntranetWare Cluster Solution, refer to the Vinca High
Availability for NetWare manual.
Hardware considerations
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Do not connect nondisk devices, such as CD-ROM drives, to shared channels.
These devices will be accessible to both servers, and conflicts might arise.
v
You must cable the SCSI channels in a controller pair so that the controllers
share the same channels.
v
You must connect all disks that will be shared to the shared channels. This
includes hot-spare drives, as well as data drives.
v
All shared physical drives must be part of a logical drive or defined as a hot
spare to one or the other servers. You must remove all other physical drives from
the shared disk enclosure to ensure proper operation.
Controller considerations
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Each ServeRAID controller must have a unique controller name assigned.
v
A controller pair is a term that refers to two controllers, one in each system, that
are connected to each other through the same SCSI bus.
v
Do not change the controller name on both ServeRAID controllers in a pair at the
same time. Doing so can cause a problem, such as a server lock-up.
v
Each ServeRAID controller, and controller pair, must have a different SCSI
initiator ID assigned to the shared channels. For example, set one server, Server
A, to ID 6, and set the other server, Server B, to ID 7. The setup instructions
describe this in more detail.
v
You must set the stripe-unit size of each ServeRAID controller in a pair to the
same value (8 KB, 16 KB, 32 KB, or 64 KB).
v
You cannot share hot-spare drives between controllers in a cluster pairing. If you
want hot-spare protection, each ServeRAID controller must have a hot-spare
drive defined. You must connect hot-spare drives only to shared channels. This is
in case the hot-spare drive replaces a failed shared drive. Both servers must be
able to access the drive in case a failover occurs after the shared drive fails.
v
Physical drives that are configured by one controller in the pair must appear as
ready drives to the other controller in the pair. Be sure to verify this criterion
when you add drives. Restart both servers, or scan for new devices using the
ServeRAID Manager program on both servers, to make sure the added physical
drives appear as ready drives on both servers before creating logical drives.
Array or logical drive considerations
v
The ServeRAID controller does not permit the failover of RAID level-5 logical
drives that are in a critical state; that is, a drive in a RAID level-5 array that has
failed. For this reason, do not use RAID level-5 for the quorum drive. You must
configure the quorum drive as a RAID level-1 logical drive.
Note: Define hot-spare drives in your array to minimize the time that logical
drives remain in critical state.
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IBM
®
User’s Reference: ServeRAID
™
-4 Ultra160 SCSI Controller