Technical information
29
Microsoft Cluster Server on C800
i,
G800
i
and L800
i
(Single Ended Disk Node)
Microsoft Cluster Server (MSCS) is a built-in feature of Windows NT Server, Enterprise Edition. It is a Microsoft
software product that supports the connection of two servers into a ‘cluster’ for higher availability and easier
manageability of data and applications. MSCS can automatically detect and recover from server or application failures.
It can be used to move server workload to balance utilisation and to provide for planned maintenance without downtime.
Fujitsu
C800
i/
G800
i/
L800
i MSCS Configuration
Fujitsu is offering a cost effective rack-mounted MSCS configuration based on two 800 series servers and shared disk
storage that is controlled via RAID Host Bus Adapters (HBAs). Each server has a Mylex eXtremeRAID 1100
(DAC1164P) controller (with ‘cluster aware’ firmware) connected to two standard 800 series single ended Disk Nodes
giving a maximum of 16 disks (8 per disk node). An upgrade is available that allows the addition of an extra
eXtremeRAID controller in each server to which one or two additional Disk Nodes may be attached, giving a maximum
of 32 disks (8 per Disk Node). These configurations provide extra resilience by using separately powered Disk Nodes
that can be mirrored, with the option of redundant power supply modules as well.
PRODUCT SPECIFICATION
The products specified,
team
server
C800
i
cluster,
team
server
G800
i
cluster
and
team
server
L800
i
cluster
, are
configurations based on MSCS. No changes or additions have been made to MSCS - this is a Microsoft product and
comes as part of Windows NT Server, Enterprise Edition 4.0.
MSCS supports fail-over on a 2-node configuration enabling recovery from common server and application failures.
Clusters can be managed via an MSCS graphical administration tool. In addition, MSCS APIs are available from
Microsoft to enable scaleable, cluster-aware applications to be created.
The Mylex eXtremeRAID 1100 (DAC1164P) controller has the following features:
•
Ultra2/LVD speed - 2 Channels
•
Up to 64MB Cache (32MB standard)
•
RAID levels JBOD, 0, 1, 3, 5, 0+1, 10, 30 and 50
•
Global Array Manager
RAID Levels
As stated above, RAID levels JBOD, 0, 1, 3, 5, 0+1, 10, 30 and 50 are supported. This gives flexibility in that users are
not restricted to RAID 1 mirroring but can have a mixture of RAID types. However, users should be aware that (say)
loss of a disk node in a non-mirrored RAID configuration could result in significant down-time while the repair takes
place.
•
The RAID controller groups disk drives in ‘drive packs’ up to a maximum of eight disks per pack.
•
Each RAID array is built using a ‘drive pack’ and thus the maximum number of disks in an individual RAID array is
8, the minimum for each pack depends upon the RAID level – see above.
•
The resulting RAID array is called a ‘logical drive’ and appears to Windows NT as a single disk drive that can be
assigned a drive letter. The maximum number of logical drives per 2-channel eXtremeRAID controller is 32.
•
To overcome the eight disk limit per disk array the RAID controller supports ‘spanning’. If two disk packs of 8 x
18GB drives are defined, without spanning, the controller would present this as two separate logical drives. With
spanning, although two RAIDs have been defined, they are spanned together to create a single logical drive of twice
the size. Spanning also makes more efficient use of different disk capacities. If three disks of 9GB and three disks of
18GB are installed, using spanning, a single logical drive using the full capacity of all drives (81GB) can be
achieved. Note the figures above do not include the overhead for redundant information. Spanning requires
consecutive drive packs with the same number of disk drives and the maximum number of drive packs which can be
spanned is four.
•
The RAID controller supports global hot spare. Any device, which is not included in a drive pack is automatically
regarded by the controller to be a global hot spare. Hot spare drive(s) must be no smaller than the largest disk in the
array (for example if a two hot spares must be available to two separate RAID 1 arrays, one using 9GB and one
using 18GB drives, then the hot spares should both be 18GB)
•
The eXtremeRAID Controller is a hardware RAID device – users should not attempt to use any NT (software)
RAID configurations in conjunction with this.