EMC Clariion: Quick Refresher 1

Optional software for EMC Clariion

EMC MirrorView for remote mirroring
EMC SnapView for creating snapshots and clones
EMC SAN Copy for copying data between storage systems.

Two storage processors (SP) manage the EMC Clariion hardware RAID features. All Clariion has two SP.

The main hardware difference in base CX700 from CX500/CX300 is that CX700 comes with a Storage Processor Enclosure (SPE) and, in addition, requires at least one 2 Gbit Disk Array Enclosure (DAE2) with 15 Fibre Channel (FC) disks.

Clariion System	Max DAE2	Max Disks
CX300	4*	60
CX500	8*	120
CX700	16	240

*Including 2-Gbit Disk Processor Enclosure (DPE2)

Clariion System	Max. Switch Ports per Storage Processor (SP)	Max. Disk Ports per SP	Max. Server Ports Connection per SP	Max. Server Ports Connection per system
CX300	2	1	32	128
CX500	2	2	64	256
CX700	4	4	64	512

EMC Clariion uses switch fabric and FC-AL topologies. The maximum optical cable length between CX300/500/700 and a server/switch ranges from 150 to 500 meters depending on cable type and speed (extended up to 60 kms with extenders). EMC recommends single-initiator switch zoning, i.e. different zones for different initiators.

The shared (direct or switched) installation require EMC Access Logix software to control LUN access. The clustered-direct installation can use cluster software controlling LUN access.

Switch zoning can prevent communication with an SP but not with specific LUNs attached to an SP. Storage Groups are required for access control with LUNs. Storage Group is a group of LUNs within storage system assigned to specific servers and inaccessible to others. Access Logix enforces the servers permission to a storage group.

Clariion supports five RAID levels (RAID 5, 3, 1, 0, 1/0) and two other disk configurations (individual unit, global "hot" spare). An additional type of redundant disk, remote mirror for any RAID except hot spare.

One RAID 5 (Individual Access Array) group, consists of three to sixteen disks, offers excellent read performance. Up to 128 LUNs can be created with in one RAID 5 group.