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Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

 
ronn48
Advisor

EMC Clariion cx4/960 ioscan EXTREMELY slow

Hello gurus.

 

I have a pair of rx7640's hooked up to a cx4-960 Clariion.  Along with a multitude of other headaches, the ioscan -fnC disk is taking forever to return, (sometimes up to 5 - 7 minutes.)

 

The Clariion is setup with 6 luns through a Brocade 5100B switch.I can see no issues with the fiber cards on the system, (AH401A.)  Any ideas? 

 

Thank you!

 

Ron

15 REPLIES 15

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

What OS release are you running? If you are on 11.31 (11iv3) you can issue the following to at least determine what element is taking so long to scan:

 

ioscan -P ms_scan_time

 


I am an HPE Employee
Accept or Kudo
ronn48
Advisor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Thanks Duncan!!

 

I ran that command, (I'm running 11.31.)  Everything comes back in milli seconds, except for anything coming off our fiber cards.  All the lunpaths, and EMC disks are into the 2 and 3 minute range. 

 

Any ideas where to go from here?

Pete Randall
Outstanding Contributor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Unless you're looking for newly created LUNs, run ioscan with the -k switch to scan the kernel structures rather than the actual hardware:  ioscan -kfnC disk


Pete
ronn48
Advisor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Thanks Pete!!

 

That worked as advertised!  However, upon futher frustration, I found that anything fiber related is very, VERY slow to respond.  That includes any powermt command, starting or stopping the Unisphere agent, or even just listing the fiber cards.  Booting the system is very slow too.  It seems to hang starting and configuring powerpath or unisphere.

 

I'm trying to rule out my system(s) that are hooked up to the cx4. 

Pete Randall
Outstanding Contributor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Glad that helped, Ron.  When you get an answer that you like, you can reward the responder by clicking on the kudos star.

 

Pete (I work for kudos) Randall


Pete
ronn48
Advisor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Kudos awarded Pete.  Thanks again.  Any thoughts on my response?  We're getting to a critical phase here.  I am working overseas right now, and have to leave in 3 days for a medical semi-emergency.  I'd like to get at least connected before I go.  At least from there I can VPN in and work on from whatever morgue I'm laying in.

Pete Randall
Outstanding Contributor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Ron, I wish I could offer you some further assistance but I know absolutely nothing about EMC other than that it's spelled eee em cee.


Pete
ronn48
Advisor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

Thanks Pete.  I appreciate your help.  This is getting so frustrating, espcially with the language barrier, I'm beginning to spell EMC using different letters.

Matti_Kurkela
Honored Contributor

Re: EMC Clariion cx4/960 ioscan EXTREMELY slow

I'm not a SAN administrator, but here are some thoughts:

 

Clariion is EMC's line of active/passive arrays. This means each disk/LUN should normally be accessed only through the SAN path that goes through the primary storage controller. If the non-primary controller is used to access the disks, it triggers a "trespass event" in the storage system, causing the primary controller to hand over the control of the disk/LUN to the other controller. The controller cannot serve disk requests while a trespass event is being handled, and the design intent is that it should only happen when there are problems with the primary controller or the SAN path(s) leading to it. Your storage administrator should be able to check if there is an excessive amount of trespass events.

 

HP-UX 11.31 can handle this type of storage, although according to EMC documentation, a March 2008 or later release of 11.31 is required. With an active/passive array and HP-UX 11.31, you should strongly prefer the new Agile DSFs (/dev/disk/diskNN or /dev/rdisk/diskNN) over of the old legacy DSFs (/dev/[r]dsk/cXtYdZ). You might even want to completely disable the old legacy DSFs (rmsf -L).

 

We once had a 11.31 system connected to an active/passive array of another manufacturer. It also behaved abysmally slow, until we found that our standard monitoring package (BMC Patrol with an old version of Hardware Sentry module) was using the legacy DSFs to monitor the state of all the disks it saw. It repeatedly polled each legacy DSF... and since each legacy DSF was associated with a specific SAN path, this kept triggering trespass events in the storage, and those frequent trespass events totally ruined the performance. The fix was to 1.) disable the legacy DSFs to prevent any other program from causing the same problem, and 2.) to update the Hardware Sentry module to a version that could actually use the new agile DSFs to monitor the local disks.

 

Either you or your SAN administrator (or whoever has the required EMC Powerlink account) should log in to the powerlink.emc.com website and find the latest version of a document titled "EMC Connectivity Guide for HP-UX". It is located in path:

Home > Support > Technical Documentation and Advisories > Host Connectivity/HBAs

> Installation/Configuration

 

It has a chapter titled "Configuration requirements for VNX series and CLARiion support with 11iv3" (starting at page 186 of the current version of the document). With your SAN administrator, you should carefully double-check each point mentioned: it has been my experience that active/passive arrays can require a higher level of attention to configuration details than the active/active ones.

 

Note that those requirements don't mention PowerPath at all, so I must assume you must comply with them, whether you're using PowerPath or not.

MK