# Ngx\_slab\_alloc() failed: no memory (not push, not key space)

**URL:** <https://www.ruby-forum.com/t/ngx-slab-alloc-failed-no-memory-not-push-not-key-space/229603>\
**Category:** NGINX\
**Created:** [January 10, 2013, 5:02pm UTC](https://www.ruby-forum.com/t/ngx-slab-alloc-failed-no-memory-not-push-not-key-space/229603 "2013-01-10T17:02:12Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Maxwell\_Lamb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ba9def/32.png) [@Maxwell\_Lamb](https://www.ruby-forum.com/u/Maxwell_Lamb)\
**Post date:** [January 10, 2013, 5:02pm UTC](https://www.ruby-forum.com/t/ngx-slab-alloc-failed-no-memory-not-push-not-key-space/229603/1 "2013-01-10T17:02:12Z")

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Hi Folks,

As ever, thanks for the mindblowingly great webserver.

Unfortunately, we’ve run into an odd little issue.

We’ve recently started auto-scaling at AWS, and we add and remove  
upstream hosts from the config via a dinky shell script which checks for  
hosts in the autoscaling group via the AWS API, and just adds them  
to/removes them from the config appropriately.

After modifying our upstream conf, we do

service nginx configtest

which if successful is followed by

service nginx reload

so far, so good.

Our config is pretty straightforward, and looks a bit like

upstream apache\_v5 {  
server 10.0.1.81:80;  
server 10.0.1.78:80;  
server 10.0.1.218:80;  
server 10.0.1.96:80;  
server 10.0.1.71:80;  
server 10.0.1.97:80;  
server 10.0.1.237:80;  
server 10.0.1.224:80;  
server 10.0.1.66:80;  
server 10.0.1.51:80;  
server 10.0.1.21:80;

fair;  
}

This all works beautifully for a while, but after a number of reloads  
and config modifications (no particular number we’ve been able to  
establish), each reload results in

ngx\_slab\_alloc() failed: no memory

and no reload of the config, preventing us from adding or removing  
further upstream hosts without completely restarting nginx. There are no  
errors preceding this, and on each subsequent reload, it reports the  
same error.

We thought this may have been related to proxy buffers, so we decreased  
both their size and number, but this has had no impact.

Additionally, while there’s no particular pattern in terms of an  
absolute number of reloads that we’ve been able to determine, the two  
nginx entry servers we’re currently using both exhibit the same  
behaviour at the same time. We’re running 1.0.14. We haven’t tried with  
a more up-to-date version just yet, in the hope that this may be an  
obscure known issue.

Any help/insight/suggestions would be much appreciated!

Thanks,

Max