Clariion Basics: DAE, DPE, SPE, Drives, Naming Conventions and Backend

Architecture

DAE: Disk Array Enclosure

DPE: Disk Processor Enclosure

SPE: Service Processor Enclosure

A DAE, DPE and SPE does sound similar to each other, but below you will see the major differences between them.

The picture above is a diagram of a Clariion Backend Architecture. Drives are enclosed in DAE’s and Service Processors in DPE’s or SPE’s depending on the model types.

DAE: Disk Array Enclosure

Each Disk Array Enclosure (DAE) holds 15 drives, count starts from 0 to 14.

DPE: Disk Processor Enclosure

The CX200, CX300, CX400 and CX500 have DPE’s installed in them that can hold 15 drives in the front with 2 Service Processors in the back.

SPE: Service Processor Enclosure

With CX3’s, CX4’s, CX600 and CX700, the SPE holds the Service Processors in the backend with cooling fans in the front end.

Architecture

CX200, CX300, CX3-10 has one bus/loop

CX400, CX500, CX600 has two bus/loops

CX700, CX3-20, CX3-40, CX3-80 has 4 bus/loops.

With more bus / loops you can expect more throughput. The Clariion CX700’s and the new CX3’s & CX4’s have more buses than the traditional CX200, CX300, CX400 and CX500.

All data from host goes to cache and is queued to be written on disk through this backend bus / loops. The speed of backend bus / loop on a CX series of machine is 2Gb, with CX3’s it jumps up to 4 Gb and with CX4’s to 8GB per second.

Also the bus/loop initiates at the SP level and goes up to the DAE’s which have LCC (Link Control Cards). Each LCC is where the bus / loop from the previous DAE/SP comes in and further daisy chains to the one above it, creating a true chained environment and protecting from single points of failure. All LCC’s are connected (loop) using HSSDC (cables). These HSSDC cables and LCC cards are hot swappable which will not cause an outage on the machine. There are Power Supplies on each SPE, DAE, DPE allowing hot replacements on those while the machine is functional. Based on your environment these replacements might possibly cause some performance issues or I/O bottleneck during the replacement window.

Addressing

Part of Architecture of Clariion is the Addressing scheme. To be able to properly understand the Clariion functionality and its backend working, the addressing scheme is very important.

Based on the model number you will have X number of buses.

For example

CX200, CX300, CX3-10 has one bus/loop

CX400, CX500, CX600 has two bus/loops

CX700, CX3-20, CX3-40, CX3-80 has 4 bus/loops.

Each bus is numbered as BUS 0, BUS 1, BUS 2 and BUS 3 depending on the model types.

Each DAE (Disk Array Enclosure) located on the BUS is numbered based on the actual physical loop number running into it. Again numbering starts at 0.

So for a CX700, if you have 4 Buses and 8 DAE’s you will have your addressing as follows:

Bus0_Enclosure0

Bus1_Enclosure0

Bus2_Enclosure0

Bus3_Enclosure0

Bus0_Enclosure1

Bus1_Enclosure1

Bus2_Enclosure1

Bus3_Enclosure1

And so forth…..the picture above explains that in a CX500 with 2 bus / loops.

The idea is the SPE/DPE is where the bus/loop starts and runs into the DAE (enclosures) assigning them a unique ID for communication and expansion purposes.

Further to add some complexity to the mix, each DAE can have 15 drives installed in it starting at Slot 0 and going to Slot 14.

To the equation above with the bus and enclosure, we have BUS X_ENCLOSURE X, now with the disk info included we have BUS X_ENCLOSURE X_DISK XX in short called B_E_D.

Disk 9 installed on Bus 0, Enclosure 0, would designate it as Bus0_Enclosure0_Disk9 or in short 0_0_9.

For the 2nd drive installed in Bus 2, Enclosure 0, you would have the address as ??????

????

????

????

????

????

2_0_1

(Remember the numbering starts at 0; we are talking about the 2nd drive.)

Why is all this information necessary????

Good idea to know exactly where your data is sitting, helps you with parts replacement, troubleshooting and also figuring out disk contention or possibly help you design your environment with your applications and database, so you can put certain apps on certain buses, enclosures and drives (let’s say your ORACLE needs 15K drives and your backups need ATA drives). You will be able to configure all of it using LUNS, MetaLUNS, RAID Groups, Storage Groups, etc.