EMC-symmetrix DMX series configuration issues.

[jeevarajkn]

Hi Admins,

My storage is EMC-Symmetrix DMX series and my ioscan -fnkC fc and powermt gives below output in HPUNIX 11.23 server.

>ioscan -fnkC fc
Class I H/W Path Driver S/W State H/W Type Description
========================================================================
fc 0 0/3/1/0/4/0 fcd CLAIMED INTERFACE HP A9784-60002 PCI/PCI-X Fibre Channel FC/GigE Combo Adapter (FC Port 1)
/dev/fcd0
fc 1 0/6/1/0/4/0 fcd CLAIMED INTERFACE HP A9784-60002 PCI/PCI-X Fibre Channel FC/GigE Combo Adapter (FC Port 1)
/dev/fcd1

>powermt display dev=all
Symmetrix ID=000290300315
Logical device ID=0044
state=alive; policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
---------------- Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
10 0/6/1/0/4/0.2.0.0.0.1.0 c10t1d0 FA 1cA active alive 0 0
8 0/3/1/0/4/0.1.0.0.0.1.0 c8t1d0 FA 16cA active alive 0 0

As am new in storage setup can any one explain me the symmetrix arichitectue with respct to my configuration. As I have two FC card but powermt shoes only one channel is configured. Is I have any risk on this?

Thanks in advance.

Reg
Jeevaraj

[skt_skt]

"As am new in storage setup can any one explain me the symmetrix arichitectue with respct to my configuration. As I have two FC card but powermt shoes only one channel is configured. Is I have any risk on this"

You have two FC cars and powermt INDEED show two paths , one through each HBA. Symmtrix uses active/active concept with regards to path. The FA ports used are 1A and 16A which indeed follow the "rule of 17" which ideally takes care of the redundancy from array perspetive. U also have the right policy set and no Queue IOS reported and all looks good.

[Yaniv Valik]

Hello Jeevaraj,

As ioscan points, you have 2 HBAs:
0/3/1/0/4/0 fcd0
0/6/1/0/4/0 fcd1

powermt is a EMC PowerPath command used to manage SAN I/O multipath. The output shows that for device 0044 on 315, you have TWO paths - c10t1d0 and c8t1d0. You may further see that the "HW path" reported by powermt per path matches the ioscan "HW path". You can also see that each is associated with a different controller id (although it's not a good idea to count on that).
So there's path redundancy which is good for high availability.

The I/O policy is set to SymmOpt which is good since it has the advantages of load balancing - optimal for performance.

My only remark is that sometimes admins choose to configure additional paths on the same HBAs for the same and/or other storage interfaces (FAs) - crossing fc0 with 1cA, etc or just configuring other FAs for the same HBA.
This could yield availability and performance improvements or just be overdoing, depending on the target system (availability - by eliminating possible single points of failure in the SAN network, performance - for example, on a TSM server or on a dbserver with intensive I/O).


Yaniv
Continuity Software

[IBaltay]

Hi,
this could help you:
http://www.retrospect.com/assets/wp_powerpath_symm_clariion_en.pdf

[Michal Kapalka (mikap)]

hi,

more about EMC symmetrix architecture can be found :

http://www.emc.com/collateral/hardware/solution-overview/c1011-symm-dmx-architecture-prod-desc-gd.pdf

commands for configuring of symmetrix :

http://storage.folmer.be/

before you will try to use this commands, you need to be sure what they are doing.

your configuration is simple one path per HBA, FA 1cA means = FC director 1c - port 0

fc direcotr could be 1[a-d] - port 0 - 1

a example from masking of the luns for specified FC director

/usr/symcli/bin>symmaskdb -sid 2044 list database -dir 8d

Symmetrix ID : SERIAL_NUMBER

Database Type : Type5
Last updated at : 09:59:53 PM on Wed Mar 18,2009

Director Identification : FA-8D
Director Port : 0

User-generated
Identifier Type Node Name Port Name Devices
---------------- ----- --------------------------------- ---------
210000e08b854d32 Fibre 210000e08b854d32 210000e08b854d32 01E4
02CE:02D1
10000000c9836e8b Fibre 10000000c9836e8b 10000000c9836e8b 01F8
02D6:02D9


mikap