[auth_digest:notice] [pid 29978] AH01757: generating secret for digest authentication ...
[core:emerg] [pid 29978] (28)No space left on device: AH00023: Couldn't create the authdigest-opaque mutex 
[auth_digest:error] [pid 29978] (28)No space left on device: AH01760: failed to create lock (opaque_lock) - all nonce-count checking, one-time nonces, and MD5-sess algorithm disabled
[:emerg] [pid 29978] AH00020: Configuration Failed, exiting

Shared Memory Limitsを超えているよう。

# ipcs | wc -l
4107

# ipcs -l

------ Messages Limits --------
max queues system wide = 479
max size of message (bytes) = 8192
default max size of queue (bytes) = 16384

------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 18014398509465599
max total shared memory (kbytes) = 18014398442373116
min seg size (bytes) = 1

------ Semaphore Limits --------
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 32
semaphore max value = 32767

# ipcrm -a
root@r-947-VM:~# ipcs

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages    

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status      
0x00000000 15499590   root       600        1000       3          dest         

------ Semaphore Arrays --------
key        semid      owner      perms      nsems