HP StorageWorks Scalable File Share System Installation and Upgrade Guide Version 2.2

I–1
I Configuring multiple servers with an EVA4000 array
In a typical HP SFS system, there is one EVA4000 array for each Object Storage Server in the system (that
is, a pair of EVA4000 arrays for each server pair). However, to serve more of the available bandwidth from
the EVA4000 arrays, it is possible to have system configurations where a pair of EVA4000 arrays is
attached to more than one pair of Object Storage Servers.
The possible alternatives are as follows:
• One EVA4000 array, two Object Storage Servers
In this configuration, Object Storage Servers are added in groups of four and EVA4000 arrays are
added in pairs.
• One EVA4000 array, four Object Storage Servers
In this configuration, Object Storage Servers are added in groups of eight and EVA4000 arrays are
added in pairs.
Such configurations are only desirable in the following circumstances:
• Configurations with more than two Object Storage Servers per EVA4000 array when the
predominant file system operation is READ. Attaching more than two Object Storage Servers to the
EVA4000 arrays does not provide extra bandwidth for WRITE operations.
• A Gigabit Ethernet interconnect is used to connect client nodes to the servers in the HP SFS system
and it is not possible to configure the servers with either a bonded or a dual Gigabit Ethernet
interconnect.
For example, a ratio of four servers for one EVA4000 array is not necessary to achieve the maximum
bandwidth if each server can have dual Gigabit Ethernet interconnect. In such a configuration, a ratio
of two servers to one array is expected to be sufficient (as in configuration 5 in the table below).
In a typical system where a pair of EVA4000 arrays is attached to only two Object Storage Servers, the
arrays are configured to have two disk groups, with one OST LUN in each disk group. In systems where a
pair of EVA4000 arrays is attached to four Object Storage Servers (that is, two Object Storage Servers per
EVA4000 array), two OST LUNs must be created in each disk group on the array. If the pair of EVA4000
arrays is attached to eight Object Storage Servers (that is, four Object Storage Servers per EVA4000), four
OST LUNs must be created in each disk group.
The following table shows the performance that may be expected in the possible system configurations. All
figures other than estimates were obtained using eight client nodes.
Interconnect Type No. of Object Storage
Servers Per EVA4000
array
EVA4000 Write
Bandwidth
(MB/sec)
EVA4000 Read
Bandwidth
(MB/sec)
1 Gigabit Ethernet 1 100 100
2 Gigabit Ethernet 2 200 200
3 Gigabit Ethernet 4 250 350
4Dual Gigabit Ethernet 1 200
1
1. Estimate
200
1
5Dual Gigabit Ethernet 2 250
1
350
1
6Dual Gigabit Ethernet 4 250
1
350
1
7 Voltaire InfiniBand,
Quadrics, or Myrinet
1280350