I've had /var/log hit 100% 2x in the last week, Was able to get some error and syslog files off as, until I ran 

sudo /etc/rc.d/rc.nginx restart

and then was able to pull diagnostics.

In the logs I found thousands of line like:

Aug 17 04:40:15 fractal nginx: 2020/08/17 04:40:15 [error] 31737#31737: *955988 nchan: error publishing message (HTTP status code 507), client: unix:, server: , request: "POST /pub/cpuload?buffer_length=1 HTTP/1.1", host: "localhost"
Aug 17 04:40:15 fractal nginx: 2020/08/17 04:40:15 [crit] 31737#31737: ngx_slab_alloc() failed: no memory
Aug 17 04:40:15 fractal nginx: 2020/08/17 04:40:15 [error] 31737#31737: shpool alloc failed
Aug 17 04:40:15 fractal nginx: 2020/08/17 04:40:15 [error] 31737#31737: nchan: Out of shared memory while allocating channel /disks. Increase nchan_max_reserved_memory.
Aug 17 04:40:15 fractal nginx: 2020/08/17 04:40:15 [error] 31737#31737: *955989 nchan: error publishing message (HTTP status code 507), client: unix:, server: , request: "POST /pub/disks?buffer_length=1 HTTP/1.1", host: "localhost"
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [crit] 31737#31737: ngx_slab_alloc() failed: no memory
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [error] 31737#31737: shpool alloc failed
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [error] 31737#31737: nchan: Out of shared memory while allocating channel /cpuload. Increase nchan_max_reserved_memory.
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [error] 31737#31737: *955990 nchan: error publishing message (HTTP status code 507), client: unix:, server: , request: "POST /pub/cpuload?buffer_length=1 HTTP/1.1", host: "localhost"
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [crit] 31737#31737: ngx_slab_alloc() failed: no memory
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [error] 31737#31737: shpool alloc failed
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [error] 31737#31737: nchan: Out of shared memory while allocating channel /var. Increase nchan_max_reserved_memory.
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [alert] 31737#31737: *955991 header already sent while keepalive, client: 10.10.10.14, server: 0.0.0.0:443
Aug 17 04:40:16 fractal kernel: nginx[31737]: segfault at 0 ip 0000000000000000 sp 00007ffea6b931f8 error 14 in nginx[400000+21000]
Aug 17 04:40:16 fractal kernel: Code: Bad RIP value.
Aug 17 04:40:16 fractal nginx: 2020/08/17 04:40:16 [alert] 17122#17122: worker process 31737 exited on signal 11

Another thing I noticed was that on the Dashboard page, the bars for the cores weren't showing activity.

 

From what I have read, this can be from 'other' browsers. I use Opera and Chromium.

 

fractal-diagnostics-20200817-1654-PLUS.zip

Running 6.9.0 Beta 25
Exact same issue.  Over and Over:

Aug 27 06:41:24 Rocinante nginx: 2020/08/27 06:41:24 [alert] 3173#3173: worker process 30662 exited on signal 6
Aug 27 14:51:09 Rocinante nginx: 2020/08/27 14:51:09 [alert] 3173#3173: worker process 15340 exited on signal 6
Aug 27 14:51:09 Rocinante nginx: 2020/08/27 14:51:09 [alert] 3173#3173: worker process 15371 exited on signal 6
Aug 27 14:51:10 Rocinante nginx: 2020/08/27 14:51:10 [crit] 15372#15372: ngx_slab_alloc() failed: no memory
Aug 27 14:51:10 Rocinante nginx: 2020/08/27 14:51:10 [error] 15372#15372: shpool alloc failed
Aug 27 14:51:10 Rocinante nginx: 2020/08/27 14:51:10 [error] 15372#15372: nchan: Out of shared memory while allocating message of size 6523. Increase nchan_max_reserved_memory.
Aug 27 14:51:10 Rocinante nginx: 2020/08/27 14:51:10 [error] 15372#15372: *2211872 nchan: error publishing message (HTTP status code 500), client: unix:, server: , request: "POST /pub/disks?buffer_length=1 HTTP/1.1", host: "localhos
t"
Aug 27 14:51:10 Rocinante nginx: 2020/08/27 14:51:10 [error] 15372#15372: MEMSTORE:00: can't create shared message for channel /disks
Aug 27 14:51:11 Rocinante nginx: 2020/08/27 14:51:11 [crit] 15372#15372: ngx_slab_alloc() failed: no memory
Aug 27 14:51:11 Rocinante nginx: 2020/08/27 14:51:11 [error] 15372#15372: shpool alloc failed
Aug 27 14:51:11 Rocinante nginx: 2020/08/27 14:51:11 [error] 15372#15372: nchan: Out of shared memory while allocating message of size 6523. Increase nchan_max_reserved_memory.
Aug 27 14:51:11 Rocinante nginx: 2020/08/27 14:51:11 [error] 15372#15372: *2211879 nchan: error publishing message (HTTP status code 500), client: unix:, server: , request: "POST /pub/disks?buffer_length=1 HTTP/1.1", host: "localhos
t"
Aug 27 14:51:11 Rocinante nginx: 2020/08/27 14:51:11 [error] 15372#15372: MEMSTORE:00: can't create shared message for channel /disks
Aug 27 14:51:11 Rocinante nginx: 2020/08/27 14:51:11 [alert] 3173#3173: worker process 15372 exited on signal 6

 

Did either of you ever find a solution?