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fork failed: Resource temporarily unavailable

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Rahul Rai_1
Frequent Advisor

fork failed: Resource temporarily unavailable

Hi Team,

How are you?

I have a request, DBA is getting the following error when they try to ssh to host: oracle's password: warning: Disconnected protocol error (fork failed: Resource temporarily unavailable). Connection to host closed. Database developers can't open sessions.

As per my understanding, if I am not wrong,
>fork failed: Resource temporarily unavailable

It means that the SSH daemon running on that particular machine,can't find free resources (memory, number of processes, number
of open files, etc.)

Thanks in advance for your support.

Regards,
Rahul Rai.
8 REPLIES
F Verschuren
Esteemed Contributor

Re: fork failed: Resource temporarily unavailable

option 1:
You system has properly insufficient resources, especially in OV environment, make sure youe swapspace have 2x of size of your physical memory.

swapinfo -tam will tell you the status of the system.
Matti_Kurkela
Honored Contributor
Solution

Re: fork failed: Resource temporarily unavailable

Your understanding is correct.

If a system displays "fork failed" errors, it usually means there is a serious problem: a runaway memory leak may have caused one application to "eat" all the available memory, or the process table is full (maybe because of some process is leaving a lot of child processes in a zombie state, or something is starting new processes without limit).

Often this lack of resources may cause some of the system daemons to die. If you can stop the process that is hogging system resources without rebooting the server, you should check that all necessary system daemons are still running.

If you cannot log in normally to see what is going on, try logging in as root from the system console. The console has a slight advantage over regular logins when the system is low on resources.

It is possible that the resource shortage is so severe you cannot log in to fix the system. In that case, you may have to force the system to reboot using the TOC/reset button, or the equivalent Management Processor function.

The TOC button/function causes the system to create a crash dump. If you have a support agreement with HP, you can send the dump to HP for analysis: the results will tell you more about the problem and possibly identify the program that was causing it.

MK
MK
Ganesan R
Honored Contributor

Re: fork failed: Resource temporarily unavailable

Hi Rahul,

Most of the time this error indicates swap/memory resource bottleneck.
Best wishes,

Ganesh.
UVK_1
Advisor

Re: fork failed: Resource temporarily unavailable

As you might be aware what does that error mean but I though of bringing it up here.

fork is trying to creat a process.

It could fail due to numerous reason, but as pointed out by our friends above it mostly occurs due to resources consraints on the system, and the message ur getting points the same direction

At times you might also see this fork failed. when u reach the max limit of process allowed for user. thought the message u get is different there.
Rahul Kumar Rai
Occasional Visitor

Re: fork failed: Resource temporarily unavailable

Hi Firends,

Thanks for your reply,

I want to confirm one thing, on the host every thing is working properly like memory utilization cpu utilization I/O rate is now perfect,
so can I close this request? or is there any thing to cross check.

waiting for your reply.

Regards,
Rahul Rai
Dennis Handly
Acclaimed Contributor

Re: fork failed: Resource temporarily unavailable

>can I close this request? or is there any thing to cross check.

Unless you have changed something, the problem may occur again.
Did you increase swap? Did you increase nproc(5) or maxuprc(5)?

You may want to monitor these 3 things.
Rahul Rai_1
Frequent Advisor

Re: fork failed: Resource temporarily unavailable

Thank you Friends,

Dennis for the time being I am going to close fork error request, I will keep in my mind if in future I am facing this issue I will schedule for reboot first and will increse these kernel parameter.

Thanks Dennis and to all friends.

Regards,
Rahul Rai.
Rahul Rai_1
Frequent Advisor

Re: fork failed: Resource temporarily unavailable

keep it up guys!