I've got a tiny server in my house which I use for file server and hosting test web sites for my clients, among other things. It uses backuppc for backups. The machine is a MSI Cubi N, backing up to a USB3 external hard drive.
Some time ago backups stopped, and I realized it was due to timing isues: I start/stop backuppc at certain times so I can stop the file server (seafile) and make a correct backup.
The backup speed dropped dramatically. Look at the difference between 926 and 938 (21.19 Mb/s vs 8.16 Mb/s, and dropping):
Totals Existing Files New Files
Backup# Type #Files Size/MB MB/sec #Files Size/MB #Files Size/MB
----------------------------------------------- ------------------- ----------------
921 full 150677 116423.3 14.47 148314 116345.7 3183 77.8
926 full 86535 106951.6 21.19 78508 106635.9 28944 319.2
938 full 1071385 144205.9 8.16 1063546 144084.1 9680 173.4
945 full 1245914 158024.8 6.57 1080617 152874.0 168331 5201.9
946 incr 189 24.4 0.03 135 1.0 169 23.3
No changes were made on the server, neither software or hardware.
I'm a software engineer, not an administrator, and I don't know what to look at. The hdd seems to work well, I mirrored it yesterday to another one and the speed was quite decent. The backups are not compressed, and the server has 4Gb of ram and practically nothing running on it (it has 3Gb free just now)
This is the status of the server just before shutting down backuppc, I can't see anything strange here:
top - 06:29:06 up 2 days, 9:53, 0 users, load average: 2,55, 1,96, 1,66
Tareas: 159 total, 1 ejecutar, 158 hibernar, 0 detener, 0 zombie
%Cpu(s): 1,7 usuario, 0,5 sist, 0,0 adecuado, 92,7 inact, 5,0 en espera, 0,
KiB Mem : 3897616 total, 108876 free, 387920 used, 3400820 buff/cache
KiB Swap: 2877436 total, 2286016 free, 591420 used. 3146140 avail Mem
PID USUARIO PR NI VIRT RES SHR S %CPU %MEM HORA+ ORDEN
738 root 20 0 44424 3840 3252 R 5,9 0,1 0:00.03 top
30375 root 20 0 137140 63996 1544 D 5,9 1,6 30:49.27 rsync
1 root 20 0 37988 5200 3344 S 0,0 0,1 0:08.78 systemd
2 root 20 0 0 0 0 S 0,0 0,0 0:00.09 kthreadd
3 root 20 0 0 0 0 S 0,0 0,0 0:02.55 ksoftirqd/0
5 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 kworker/0:+
7 root 20 0 0 0 0 S 0,0 0,0 2:16.81 rcu_sched
8 root 20 0 0 0 0 S 0,0 0,0 0:00.00 rcu_bh
9 root rt 0 0 0 0 S 0,0 0,0 0:00.15 migration/0
...
¿Could you please give me some clues to see what happened and how to increase performance?