ftp/tcp: accept: No buffer space available (493 Views)
Reply
Frequent Advisor
Posts: 78
Registered: ‎07-22-2003
Message 1 of 12 (493 Views)

ftp/tcp: accept: No buffer space available

Sometimes ftp and telnet connections to my HPUX server 11.00 generate following messages in the syslog.log

inetd[675]: ftp/tcp: accept: No buffer space available

Any suggestion ?


Honored Contributor
Posts: 1,179
Registered: ‎10-16-2003
Message 2 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

Sounds like you run out of virtual memory... Are there other processes complaining or crashing on you at the same time you get this message ?
Every problem has at least one solution. Only some solutions are harder to find.
Frequent Advisor
Posts: 78
Registered: ‎07-22-2003
Message 3 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

swapinfo details....

TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 3072000 42236 3029764 1% 0 - 1 /dev/vgroot/lvol2
reserve - 1116748 -1116748
memory 1553780 953156 600624 61%
total 4625780 2112140 2513640 46% - 0 -
Honored Contributor
Posts: 5,532
Registered: ‎12-11-2000
Message 4 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

check the swap and memory usage on the machine

swapinfo -ta
Honored Contributor
Posts: 763
Registered: ‎03-05-2002
Message 5 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

http://archives.neohapsis.com/archives/postfix/2002-02/1952.html

So computers don't think yet. At least not chess computers. - Seymour Cray
Frequent Advisor
Posts: 78
Registered: ‎07-22-2003
Message 6 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

Dont see any problem with the swap.
Honored Contributor
Posts: 1,179
Registered: ‎10-16-2003
Message 7 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

True. As long as this is the output at the time of the problem too...

If that is the case, then try to add a buffersize when starting the ftpd by adding a -B option in /etc/inetd.conf for the ftp daemon. Set it to a small value. And when you're add it, also set logging to see if the message is generated immediately or after some time.
Every problem has at least one solution. Only some solutions are harder to find.
Honored Contributor
Posts: 763
Registered: ‎03-05-2002
Message 8 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

To clarify (no add. points pls):
This is about accept() TCP procedure.What happens is that when server (ftp in your case) is busy client puts its request in a queue , later client timeouts but when server is free and tries to accept the connection RST bit is sent from the client ( I guess ) ,client buffers are freed from the server and server receives ENOBUFS from its TCP and complains.Ie, there was such an issue in Apache 1.x but was fixed in 2.x.What ftp server do you use, hp-ux usual?

Zeev
So computers don't think yet. At least not chess computers. - Seymour Cray
Frequent Advisor
Posts: 78
Registered: ‎07-22-2003
Message 9 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

Zeev,

It is not just FTP, there were few ocassions when telnet also reported same messages in the sylog.
The ftp version we use is 1.1.214.6

so whats the solution ?

Thanks

Honored Contributor
Posts: 1,140
Registered: ‎07-15-2002
Message 10 of 12 (493 Views)

Re: ftp/tcp: accept: No buffer space available

Steve,

you can find a lot of threads in this forum if you just search for "network " and "no buffer space".

Quickly glancing across them I found that on one occasion it was fixed by increasing the kernel parameter nstrtel, another fixed it by increasind maxdsiz.

Some indicate network patches, but you may want to take a closer look yourself.

Regards,
Bernhard
Honored Contributor
Posts: 763
Registered: ‎03-05-2002
Message 11 of 12 (492 Views)

Re: ftp/tcp: accept: No buffer space available

Steve,
Its hard to say since this message is general
regarding ENOBUFS (man accept). There were some applications that produced these messages and hanged. I think your case should be investigated, ie checking what applications are running, doing some network checks, etc. For example, you should check in syslog.log if there were another application messages before inetd reported this error.

Zeev
So computers don't think yet. At least not chess computers. - Seymour Cray
Honored Contributor
Posts: 3,814
Registered: ‎12-02-1996
Message 12 of 12 (492 Views)

Re: ftp/tcp: accept: No buffer space available

Indeed, 99 times out of ten, this message has nothing to do with availability of memory. It means that by the time the server application got around to calling accept() on the listen socket, the remote client had given-up (for wahtever reason) and aborted the connection. The exact reason why an ENOBUF is returned in this case in HP-UX 11.X is starting to get lost in the mists of time, but it had something to do with not wanting to leave the application stuck in an accept() call if that was the only connection left on the listen queue, and needing to return what applications were expected to be treating as a transient error.

Of course, some applications were not correctly treating ENOBUF as a transient error... :(

The only "fix" is to make sure the server application can get around to calling accept() in time - either by making the server application run faster, or by making the client more forgiving. Otherwise, unless it is happening a _lot_ or if apps are not correctly treating it as a transient condition, it can be safely ignored.
there is no rest for the wicked yet the virtuous have no pillows
The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the Terms of Use and Rules of Participation.