KAIO: out of OS resources, errno = 11

Hi, The following message continuously occurs in online.log and a service delay occurs. KAIO: out of OS resources, errno = 11, pid = 4784150 Below is the onstat -g sql result. My customer is using Informix 12.10.FC6 on AIX, can setting the IFMX_AIXKAIO_NUM_REQ environment variable help solve the problem? And how can I check if it has been applied? ------------------------------ SangGyu Jeong Software Engineer Infrasoft Seoul Korea, Republic of ------------------------------ #Informix

Hi SangGyu, I think is a known issue on AIX and yes setting the env variable IFMX_AIXKAIO_NUM_REQ can help. Just have a look onto below URl https://www.ibm.com/support/pages/node/80163 https://www.ibm.com/support/pages/node/662377 ------------------------------ Gaurav Kumar ------------------------------

Just to add, the maxium value for IFMX_AIXKAIO_NUM_REQ is 8192, it was increased from 4096 to 8192 in one of the older versions. I don't think there is a way to verify if the parameter is set. As far as I know, once this is enabled, the "KAIO : out of OS resources" does not appear anymore. They'll need to enable this env variable before starting oninit for it to be effective. Anyway the server has been up for 1427 days, it's time to rebounce :) ------------------------------ Casey Tan ------------------------------

Use this command to view the environment of a running process, where in this case PID is an "oninit" process ID: ps eww PID | tr ' ' '\\n' | grep = | sort Works on AIX and Linux. May need to be run as root. ------------------------------ Doug Lawry Oninit Consulting ------------------------------

Hi, yes, setting IFMX_AIXKAIO_NUM_REQ to a higher value may resolve the problem ( see also https://www.ibm.com/support/pages/node/80163 ). (Obviously, doing so will require a shutdown and restart of the Informix server.) However, I think checking the AIX kernel parameter "maxreqs" should be done as well. If found being low, it may be necessary to (also) increase it. You should be able to see the environment of a running process (i.e. "oninit" process) with the command "ps -eww <pid>". Regards, Martin -- -- DISCLAIMER-- ------------------------------ This document is intended for transmission to the named recipient only. If you are not that person, you should note that legal rights reside in this document and you are not authorized to access, read, disclose, copy, use or otherwise deal with it and any such actions are prohibited and may be unlawful. The views expressed in this document are not necessarily those of HCL Technologies Ltd. Notice is hereby given that no representation, contract or other binding obligation shall be created by this e-mail, which must be interpreted accordingly. Any representations, contractual rights or obligations shall be separately communicated in writing and signed in the original by a duly authorized officer of the relevant company. ------------------------------ ::DISCLAIMER:: The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. E-mail transmission is not guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or may contain viruses in transmission. The e mail and its contents (with or without referred errors) shall therefore not attach any liability on the originator or HCL or its affiliates. Views or opinions, if any, presented in this email are solely those of the author and may not necessarily reflect the views or opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of authorized representative of HCL is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any email and/or attachments, please check them for viruses and other defects.

Thank you for the great tip. Doug. ------------------------------ SangGyu Jeong Software Engineer Infrasoft Seoul Korea, Republic of ------------------------------

Thank you all. After further checking, I noticed that while the error message occurred, the mutex wait and the buffer wait of the INSERT session were continued. (Thanks to InformixHQ) As shown in the screenshot, the time when the application that executes the INSERT statement in multiple sessions starts and the time when the error message occurs coincide. So I am guessing the problem is that the application causes excessive INSERTs at the same time. (About 300 sessions) In summary, the IFMX_AIXKAIO_NUM_REQ environment variable, maxreqs setting, application logic improvement, and lru queue tuning should also be considered. ------------------------------ SangGyu Jeong Software Engineer Infrasoft Seoul Korea, Republic of ------------------------------

Hello Casey, Thanks for your response. This is where my customers have the longest uptime. ------------------------------ SangGyu Jeong Software Engineer Infrasoft Seoul Korea, Republic of ------------------------------

Thank you for answer. Martin. My customer is primarily considering fixing the application that is causing the problem or adjusting the application execution schedule. If the customer is unable to modify the application or the problem persists even if the application is modified, I will recommend the solutions presented here to the customer. ------------------------------ SangGyu Jeong Software Engineer Infrasoft Seoul Korea, Republic of ------------------------------

Hi, You need to set IFXM_AIXKAIO_NUM_REQ to tune your Kernel Asynchronous I/O (KAIO) subsystem. Its default value is 1024 if you does not set IFMX_AIXKAIO_NUM_REQ. Indeed, when you start your engine, Informix engine allocates a number of AIOCB structure (AIOCB = asynchronous I/O control block) specified by IFMX_AIXKAIO_NUM_REQ. The AIOCB is an Operating System structure used by Informix to manage several parameters of your asynchronous I/O requests (file descriptor, buffer location, file offset, length of your request ...) and to receive completion status information for asynchronous I/O requests.?? Informix does not increase dynamically the number of AIOCB when all AIOCB blocks are used at the same time, informix must then wait until an AIOCB is free to be reused for a new asynchronous I/O request. The default value is not enough for your current asynchronous I/O requests activity. By example, you can set IFMX_AIXKAIO_NUM_REQ to 8192 or 16000 to tune your KAIO subsystem. Regards, -- Franck Thomas ConsultiX franck.thomas@consult-ix.fr http://www.consult-ix.fr T??l??phone : 33 (0) 1 39 12 18 00 Mobile : 33 (0) 6 78 81 09 33 Fax : 33 (0) 1 39 12 18 18 Le 18/06/2020 ?? 00:34, SangGyu Jeong via IBM Community a ??crit??:

Hi, You need to set IFXM_AIXKAIO_NUM_REQ to tune your Kernel Asynchronous I/O (KAIO) subsystem. Its default value is 1024 if you does not set IFMX_AIXKAIO_NUM_REQ. Indeed, when you start your engine, Informix engine allocates a number of AIOCB structure (AIOCB = asynchronous I/O control block) specified by IFMX_AIXKAIO_NUM_REQ. The AIOCB is an Operating System structure used by Informix to manage several parameters of your asynchronous I/O requests (file descriptor, buffer location, file offset, length of your request ...) and to receive completion status information for asynchronous I/O requests.?? Informix does not increase dynamically the number of AIOCB when all AIOCB blocks are used at the same time, informix must then wait until an AIOCB is free to be reused for a new asynchronous I/O request. The default value is not enough for your current asynchronous I/O requests activity. By example, you can set IFMX_AIXKAIO_NUM_REQ to 8192 or 16000 to tune your KAIO subsystem. Regards, -- Franck Thomas ConsultiX franck.thomas@consult-ix.fr http://www.consult-ix.fr T??l??phone : 33 (0) 1 39 12 18 00 Mobile : 33 (0) 6 78 81 09 33 Fax : 33 (0) 1 39 12 18 18