topic Warren in Network Security

Cisco ASA free memory differs greatly between active/passive

stephew — Fri, 21 Feb 2020 14:04:40 GMT

Hello,

I have Cisco ASA 5525 active/passive setup with both devices syncronized, however the primary device is down to 5% free memory whilst the passive device has 76% free memory.

The version of IOS is version 9.5 (2), although a reload of both devices should resolve the issue i wanted top ask the community why such a discrepancy between the devices should exist and if there is any way to resolve the issue without reloading them.

Regards

Warren

It would be nice if you could

Richard Burts — Thu, 11 May 2017 18:57:47 GMT

It would be nice if you could figure out what is using large amounts of memory and that might help point toward a solution. I would expect some difference in memory usage between the active ASA and the standby ASA since the active ASA is doing some things and maintaining some tables that the standby ASA does not, such as the routing table, the ARP table, (and depending on how your failover is configured the translate table).

Has the free memory on the active ASA been decreasing over time? This might indicate that there is a memory leak in this version of software.

HTH

Rick

Hi Rick,

stephew — Fri, 12 May 2017 14:46:36 GMT

Hi Rick,

Thanks for your reply, the memory has been decreasing over time, in the last week it has reduced by around 4% which does indicate some kind of memory leak.

I have a scheduled reload for both devices tonight so hopefully problem will be resolved after this.

Regards

Warren

Richard Burts — Fri, 12 May 2017 15:38:29 GMT

Warren

Thanks for the additional information. If the free memory has been decreasing over time then it does sound like a memory leak. A reboot of the ASA would certainly be one way to address the immediate issue. Probably a failover from the current active ASA to the standby ASA (perhaps followed by a reboot of the first ASA) would be one way to do this. The long term solution to a memory leak is an upgrade to a different version of code.

HTH

Rick

Re: It would be nice if you could

stephew — Tue, 10 Jul 2018 14:15:21 GMT

Hi Richard,

This was resolved by reload, a few weeks later I upgraded the software and have not seen the problem since, so as a work around the reload worked but the upgrade most certainly cleared the memory leak for good.

Thanks for your help.

Kind Regards