[erlang-questions] fd=NN is larger than the largest allowed fd=255

Lukas Larsson <>
Tue Mar 17 21:42:06 CET 2015


Hello,

I believe that that limitation is determined by this piece of code:
https://github.com/erlang/otp/blob/maint/erts/emulator/sys/common/erl_poll.c#L2308-L2320

So you have to figure what is defined on Android and check that. Basho has
a guide which tells you some of the more common places to look for what
could be causing this limit:
http://docs.basho.com/riak/latest/ops/tuning/open-files-limit/.

I would first check sysconf and make sure that you are allowed to open as
many fd's as you want.

Lukas

On Tue, Mar 17, 2015 at 8:42 PM, Manju Hanasi <> wrote:

> Hi,
>
> We are using an older version of Couchbase Mobile on Android and this one
> is erlang based. We use OTP version R14B03. I know it's pretty old and it's
> time to upgrade, so bare with me.
>
> Recently we have started getting errors like "fd=NN is larger than the
> largest allowed fd=255" where NN is any value greater than 255.
>
> This is not really an OS limitation as the 'ulimit -a' on Android shows
> 1024 for open file descriptors (as found out by 'adb shell').
>
> Looks like Erlang VM is not allowing file descriptors more than 255.
>
> It would be great if we could set some environment variable or pass a
> parameter that can increase this limit (e.g.
> https://github.com/couchbase/Android-Couchbase/blob/master/src/com/couchbase/android/CouchbaseService.java#L203
> ).
>
> We tried setting "ERL_MAX_PORTS" environment variable to 1024, but we
> still get the error at 255.
>
> Unfortunately, our version doesn't support +Q parameter for increasing the
> number of ports.
>
> Is there any quick and/or hacky way to increase the fd limit beyond 255;
> for example increase it to 512 or 1024?
>
> I greatly appreciate any help in resolving this issue.
>
> Thanks
> Manju
>
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>
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