Re: z/OS 1.4-1.7 gotchas [EMAIL PROTECTED]
Taking the device offline doesn't do anything, the CHP has to be configured off to all LPARs, even those LPARs that are not activated (this is a point that is often missed). [EMAIL PROTECTED] 4/10/2008 4:17 AM Ok.. We hit this problem late last year on an IBM z9BC. I supppose the PMR is still out there on the database if anyone's got access to it. I just dug out our internal problem log for the morning's events and looked through the timeline. Our IBM support engineer first took the device offline on all LPARs, and that did not resolve the problem. We then IPL'd each LPAR; again, that did not resolve the problem. We then did a POR of the box, and the devices were then available. This is the email they (IBM) sent me: Here is the information about the problem. This a known problem and there is a microcode fix available for your machine. The intent of this TDR is to provide information to determine if Segmentation Offload is enabled, and how to disable it. Symptoms: OSA Card will lock up. Check for Segmentation Offload being active: From the z/OS console on each Image, enter D TCPIP,procname,NETSTAT,DEV. If Segmentation offload is functioning, you will see SEGMENTATIONOFFLOAD: YES for the OSA. If this specific line is not displayed, segmentation offload is not available. at this level or previously disabled There is not a NO option for SEGMENTATIONOFFLOAD. Its either YES, or not displayed. There are two ways to disable segmentation offload. The maintenance level on the system determines which one must be used If your customer has applied PK21685 or PK26905, it must be done via the configuration file. 1) If the PTFs are not applied, use the following procedure: Update the TCPIP PROFILE to comment out the START statements for the affected OSA devices. Issue the following commands every time TCPIP is restarted: MODIFY tcpipprocname,NOSEGOFFLOAD (then for each OSA) VARY TCPIP,tcpipjobname,START,osa_device_name (tcpipjobname is optional on this command in a single stack environment) If the MODIFY command is rejected with a EZZ3250I THE MODIFY COMMAND IS NOT SUPPORTED message, Then either: The system does not support Segmentation Offload. Only z/OS 1.7 and above or z/OS 1.6 with the PK02490 PTFs applied have this support, earlier systems do not have any concern with this problem. The PTFs for PK21685 have been applied, thus the following method needs to be used instead. 2) If the PTFs are applied, add the NOSEGMENTATIONOFFLOAD keyword to the GLOBALCONFIG statement in the TCPIP PROFILE. For further help with these commands, contact software support. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] Behalf Of Scott Rowe Sent: 09 April 2008 20:40 To: IBM-MAIN@BAMA.UA.EDU Subject: Re: z/OS 1.4-1.7 gotchas ??? AFIAK there is no fix, microcode or otherwise, for the segmentation offload problem. I think the default has since been changed been changed to off. Also, it did not affect old OSA cards, it affects ALL OSA Express cards. There was also no need to POR, or even IPL, to recover the card, all that is needed is to configure it offline to ALL LPARs, and then back on. - Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html Note that my email domain has changed from
Re: z/OS 1.4-1.7 gotchas [EMAIL PROTECTED]
Hmmm, and you configured if offline to all of the LPARs before you brought it back on to any of them? Sounds strange indeed. I have done this a couple times, and the only problem I have had is when one or more of the LPARs is inactive, then you have to go in though the HMC to take them off. [EMAIL PROTECTED] 4/10/2008 10:02 AM Sorry, should have made that clearer - by 'device' I meant the actual OSA itself, not the MVS devices. We did CONFIG CHP(xx),OFFLINE on all LPARs that it was defined to. You got me doubting myself for a moment there though, so I just pulled back our archived SYSLOGs for that day, and they clearly show we did take the channel off and on again with no success. Anyway, I guess that's just a mystery then. Bri - Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html Note that my email domain has changed from jo-annstores.com to joann.com. Please update your address book and other records to reflect this change. CONFIDENTIALITY/EMAIL NOTICE: The material in this transmission contains confidential and privileged information intended only for the addressee. If you are not the intended recipient, please be advised that you have received this material in error and that any forwarding, copying, printing, distribution, use or disclosure of the material is strictly prohibited. If you have received this material in error, please (i) do not read it, (ii) reply to the sender that you received the message in error, and (iii) erase or destroy the material. Emails are not secure and can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by email. Thank you. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: z/OS 1.4-1.7 gotchas [EMAIL PROTECTED]
??? AFIAK there is no fix, microcode or otherwise, for the segmentation offload problem. I think the default has since been changed been changed to off. Also, it did not affect old OSA cards, it affects ALL OSA Express cards. There was also no need to POR, or even IPL, to recover the card, all that is needed is to configure it offline to ALL LPARs, and then back on. [EMAIL PROTECTED] 4/9/2008 12:46 PM One that got us was the TCPIP profile default for the SEGMENTATIONOFFLOAD changed from NO to YES. This attempts to offload some of the TCPIP packet handling from the processor to the OSA card. If you have an old(ish - ours was from 2006/2007) version of the OSA Express/Express2 card, it will lock up under certain high workload conditions, and all IP traffic to and from the machine will stop. The only resolution is a full Power-on Reset - an IPL is not enough. There is a microcode fix for the OSA, however the workaround is to explicitly specify NOSEGMENTATIONOFFLOAD on a GLOBALCONFIG statement in your TCPIP profile, on all LPARs that run a TCPIP stack. It's a known problem apparently. We thought we'd been quite thorough in our prep too, but we missed it. Brian - Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html Note that my email domain has changed from jo-annstores.com to joann.com. Please update your address book and other records to reflect this change. CONFIDENTIALITY/EMAIL NOTICE: The material in this transmission contains confidential and privileged information intended only for the addressee. If you are not the intended recipient, please be advised that you have received this material in error and that any forwarding, copying, printing, distribution, use or disclosure of the material is strictly prohibited. If you have received this material in error, please (i) do not read it, (ii) reply to the sender that you received the message in error, and (iii) erase or destroy the material. Emails are not secure and can be intercepted, amended, lost or destroyed, or contain viruses. You are deemed to have accepted these risks if you communicate with us by email. Thank you. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
