Given:
- QNAP TS-439 Pro NAS with 4 x WD20EADS in RAID-5
- eSATA/USB Sharkoon QuickPort Pro SATA cradle
- WD20EARS
- 1.7TB data on RAID-5
Guess, how long will it take to back up 1.7TB of mostly big files to a directly connected eSATA disk using standard GUI commands?
24hours. Or something about 12MB/sec.
If I copy from Solaris (usually loaded) to NAS:
xeon% time gtar cf – store | (cd /nas/audio; gtar xvf -)
. . .
% iostat -zxnmp 5
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
174,8 1,6 22370,2 179,2 17,4 1,4 98,9 7,7 67 68 c1d0
188,4 1,6 24047,9 179,2 18,7 1,4 98,4 7,6 71 72 c2d0
0,0 1454,9 0,0 46557,7 8,4 7,8 5,8 5,4 98 98 nas:/audio
. . .
% iostat -zxnmp 5
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
174,8 1,6 22370,2 179,2 17,4 1,4 98,9 7,7 67 68 c1d0
188,4 1,6 24047,9 179,2 18,7 1,4 98,4 7,6 71 72 c2d0
0,0 1454,9 0,0 46557,7 8,4 7,8 5,8 5,4 98 98 nas:/audio
real 1h13m40.62s
user 1m7.56s
sys 17m46.44s
xeon% du -hs store
161G store
The maximum I could get was ~47MB/s. BTW, notice how evenly the load is balanced across two mirrored disks (c1d0 and c2d0). The average is 37.3MB/s
Resume: backing up to/restoring from a directly connected disk does not make any sense.