@julian
good to know this useful information, I checked on mine (not changed any redis db config when installed nodebb) so in doubt I checked, here the log file, sounds to works fine and default are
save 900 1
save 300 10
save 60 10000
and logs
[574] 17 Sep 20:02:36.228 * Background saving terminated with success
[574] 17 Sep 20:07:37.008 * 10 changes in 300 seconds. Saving...
[574] 17 Sep 20:07:37.009 * Background saving started by pid 16535
[16535] 17 Sep 20:07:37.196 * DB saved on disk
[16535] 17 Sep 20:07:37.197 * RDB: 0 MB of memory used by copy-on-write
[574] 17 Sep 20:07:37.210 * Background saving terminated with success
[574] 17 Sep 20:12:38.037 * 10 changes in 300 seconds. Saving...
[574] 17 Sep 20:12:38.039 * Background saving started by pid 16538
[16538] 17 Sep 20:12:38.227 * DB saved on disk
[16538] 17 Sep 20:12:38.228 * RDB: 1 MB of memory used by copy-on-write
[574] 17 Sep 20:12:38.239 * Background saving terminated with success
[574] 17 Sep 20:17:39.093 * 10 changes in 300 seconds. Saving...
[574] 17 Sep 20:17:39.094 * Background saving started by pid 16543
[16543] 17 Sep 20:17:39.308 * DB saved on disk
[16543] 17 Sep 20:17:39.310 * RDB: 0 MB of memory used by copy-on-write
[574] 17 Sep 20:17:39.395 * Background saving terminated with success
[574] 17 Sep 20:22:40.096 * 10 changes in 300 seconds. Saving...
[574] 17 Sep 20:22:40.097 * Background saving started by pid 16550
[16550] 17 Sep 20:22:40.276 * DB saved on disk
[16550] 17 Sep 20:22:40.277 * RDB: 0 MB of memory used by copy-on-write
[574] 17 Sep 20:22:40.298 * Background saving terminated with success
