Hi Giles,

Have you limited the ZFS arc in /etc/modprobe.d?

You should set it something manageable like 2GB

options zfs zfs_arc_max=2147483648
Cheers,

Randy

On Sun, Aug 23, 2026, at 3:35 PM, Giles Orr via Talk wrote:
I have a machine running Debian 13 that's used for:
- ripping DVDs
- ZFS 2x6TB mirror
- backing up the contents of my primary machine

But for several months it's been unstable.  In the last month I've concluded it's got a memory leak.  `htop`, `free`, and `stacer` have led me to this conclusion, but none of these seem to be able to tell me what's causing the leak.  I've watched the memory gauge in `stacer` go from "5.0GiB of 15.6GiB" to "10.2GiB" used in about 5 minutes - while I was doing nothing on the machine, and `htop` said no processes were active and nothing in particular was using more memory than usual.

It would be easiest to blame my home-built version of GNU HandBrake, but the surge of memory usage mentioned above occurred before I ever started `ghb`.  So pretty sure it's not that.  Could it be ZFS memory caching?  Is there a way to check (or control) that?

The result is that after about five days the machine is choking because it's trying to swap everything to disk (very slow because spinning disks) and around seven days it dies completely.  Prior to this supposed leak, the machine was stable and usable for months at a time, so I'd really love to hunt down and kill this bug ...  Any suggestions on how to hunt memory leaks would be much appreciated.

--
------------------------------------
Description: GTALUG Talk
Unsubscribe via Talk-unsubscribe@lists.gtalug.org
Start a new thread: talk@lists.gtalug.org
This message archived at https://lists.gtalug.org/archives/list/talk@lists.gtalug.org/message/37E45PKZAAPJVPOLDALNOSSOXCCID43Y/


Nowhere less alone than with my books, a cup of coffee, and Beethoven’s Ninth.