HP StorageWorks Scalable File Share - Manual (Page 21)

Product overview 1–5
• A server pair consisting of the administration server and the MDS server, and pairs of Object Storage
Servers
In the event of failure of the MDS server, the administration server is capable of taking over the function of
serving file system meta-data (in addition to continuing to serve the administration functions). Similarly, in
the event of failure of the administration server, the administration functions automatically fail over to the
MDS server. The HP SFS software performs this failover automatically.
In an Object Storage Server pair, each server provides independent OST services. Each server in the pair
can serve the OST services of its peer in the case of peer failure. The HP SFS software performs this failover
transparently at the servers, so that client applications do not see I/O errors.
1.1.3.2 Storage
In HP SFS Version 2.2, two types of storage are supported:
• The HP StorageWorks Enterprise Virtual Array 4000 (EVA4000)—see Section 1.1.3.2.1
• The HP StorageWorks Scalable File Share 20 Enclosure (SFS20)—see Section 1.1.3.2.2
Only one type of storage can be used in a system—that is, you cannot have a combination of EVA4000
and SFS20 arrays in your HP SFS system.
1.1.3.2.1 EVA4000 storage arrays
The EVA4000 array is a high-performance redundant array of independent disks (RAID) array. A system
configured with EVA4000 arrays is configured to have high availability, and Object Storage Servers are
organized in pairs. While each array is attached to two servers 1 , an array is normally accessed by one of
the servers only. However, if a server fails, the second server in the server pair has the ability to access the
array normally accessed by the first server. In effect, the EVA4000 arrays are also grouped in pairs.
In larger HP SFS systems where no OST services are run on the administration and MDS servers, this server
pair is configured with one dedicated EVA4000 array.
Figure 1-3 shows an overview of an HP SFS system that uses EVA4000 storage arrays. All servers in the HP
SFS system are also connected to the management network; this connection is not shown in Figure 1-3.
Figure 1-3 HP SFS system using EVA4000 storage arrays
1. It is possible to have a system configuration where EVA4000 arrays are attached to more than two Object Storage Servers. This
configuration is described in Appendix I of the HP StorageWorks Scalable File Share System Installation and Upgrade Guide.
Legend
Admin: Administration Server
MDS: Meta-data Server
OSS: Object Storage Server
EVA: EVA4000 Storage Array
MDS OSS OSS OSS OSS Admin
1 2 3 4 5 6
Connection to System Interconnect
EVA EVA EVA EVA EVA
Connection to
Site Network Connection to
Site Network
Client Population