Cloud backup over Https/webdav...

So, after a day of test - with fiber optic (100 Mo / 50 Mo - Theoric data download/upload)
- rsync manually on the nas of 750 mo = 1h30 hour
- backup jobs (local share to davfs mount via rsync) with frontview of 750 Mo and with enable compression and co = 2h30 hour
- backup job (local share to davfs mount NOT VIA RSYNC) = 1H30
- copy command under Midnight Commander = about 1h30 hour
and
- directly upload from a WinXP computer to the Cloud (without NAS) of 350 Mo = 5-10 min
?....

So I got a real problem with the performance , for example, now i run a incremental backup (diff 4.4 Gb) and with "top" commande I can see that the load is extremely high :

top - 09:41:50 up 2 days, 16:56,  1 user,  load average: 3.22, 3.82, 3.46
Tasks:  84 total,   5 running,  79 sleeping,   0 stopped,   0 zombie
Cpu(s): 19.6% us,  8.0% sy,  8.9% ni, 62.4% id,  0.2% wa,  0.2% hi,  0.6% si
Mem:    226256k total,   215744k used,    10512k free,    10384k buffers
Swap:   255968k total,     1952k used,   254016k free,    44416k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 6173 davfs2    25   0 20432  10m 2672 R 80.1  4.9 716:33.28 mount.davfs
22615 root      16   0  2976 1552 1216 R 10.4  0.7   0:00.16 top
17498 root      36  19 49568  34m 2032 R  7.0 15.7  12:50.13 minidlna
    1 root      15   0  2000  880  768 S  0.0  0.4   0:06.94 init
    2 root      34  19     0    0    0 S  0.0  0.0   0:00.07 ksoftirqd/0

Even before the install, I got bad perf (squeezebox server slow...), is it normal that the CPU Charge slow down the upload ?

or I should change some conf in the davfs2.conf ?

(or I should buy a new Netgear product with more mem & cpu ... :roll: )