Redis RDB snapshot error: reg

[Manukumar NM]

I have enough memory space where redis is running but still am getting this error why: cat openwisp2.log result: redis.exceptions.ResponseError: MISCONF Redis is configured to save RDB snapshots, but it is currently not able to persist on disk. Commands that may modify the data set are disabled, because this instance is configured to report errors during writes if RDB snapshotting fails (stop-writes-on-bgsave-error option). Please check the Redis logs for details about the RDB error.

redis log: 113008:M 10 Nov 05:01:22.060 * 1 changes in 900 seconds. Saving...
113008:M 10 Nov 05:01:22.061 # Can't save in background: fork: Cannot allocate memory
113008:M 10 Nov 05:01:28.076 * 1 changes in 900 seconds. Saving...
113008:M 10 Nov 05:01:28.078 # Can't save in background: fork: Cannot allocate memory

redis dump.rdb : df -h dump.rdb
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 99G 9.6G 90G 10% /.

Thanks in advance