I have a server that freeqently downloads large files, the problem is every time it's downloading a file, it stops all network activety from that disk. in the output bellow you can see that network activety was at `1116 mbs`

and in the second output you can see that on sdc drive was `write 391`

and network activety was dropped to `502 mbs`

than after `writes`

stops it's going up to normal, sometime it's dropping even to 60mps.

I'm wondering what's going on, because i have two other similar servers with which I don't have that problem. the only difference that i can think of, is on both of them i've centos6 and here i'm using ubuntu 12.04

```
Linux SDNRUUA 3.5.0-17-generic #28-Ubuntu SMP Tue Oct 9 19:31:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
```

No writes to disk

```
DSK | sda | busy 15% | read 240 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 15.00 | MBw/s 0.00 | avio 1.25 ms |
DSK | sdc | busy 14% | read 207 | write 0 | KiB/r 127 | KiB/w 0 | MBr/s 12.92 | MBw/s 0.00 | avio 1.33 ms |
DSK | sdf | busy 13% | read 472 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 29.56 | MBw/s 0.00 | avio 0.53 ms |
DSK | sde | busy 11% | read 391 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 24.44 | MBw/s 0.00 | avio 0.54 ms |
DSK | sdb | busy 7% | read 120 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 7.50 | MBw/s 0.00 | avio 1.17 ms |
DSK | sdd | busy 6% | read 72 | write 3 | KiB/r 128 | KiB/w 12 | MBr/s 4.50 | MBw/s 0.02 | avio 1.65 ms |
NET | transport | tcpi 90171 | tcpo 186682 | udpi 0 | udpo 0 | tcpao 27 | tcppo 48 | tcprs 1734 | udpip 0 |
NET | network | ipi 90172 | ipo 30192 | ipfrw 0 | deliv 90175 | | | icmpi 0 | icmpo 0 |
NET | p262p1 ---- | pcki 89893 | pcko 188178 | si 21 Mbps | so 1116 Mbps | erri 0 | erro 0 | drpi 0 | drpo 0 |
NET | lo ---- | pcki 275 | pcko 275 | si 129 Kbps | so 129 Kbps | erri 0 | erro 0 | drpi 0 | drpo 0
```

write to one of the disks

```
SWP | tot 31.7G | free 31.7G | | | | | | vmcom 6.0G | vmlim 47.3G |
PAG | scan 85374 | steal 85374 | stall 3 | | | | | swin 0 | swout 0 |
DSK | sdc | busy 62% | read 30 | write 391 | KiB/r 153 | KiB/w 508 | MBr/s 2.25 | MBw/s 97.03 | avio 2.90 ms |
DSK | sdb | busy 48% | read 909 | write 0 | KiB/r 127 | KiB/w 0 | MBr/s 56.79 | MBw/s 0.00 | avio 1.03 ms |
DSK | sde | busy 9% | read 337 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 21.19 | MBw/s 0.00 | avio 0.55 ms |
DSK | sdf | busy 7% | read 243 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 15.19 | MBw/s 0.00 | avio 0.54 ms |
DSK | sda | busy 5% | read 72 | write 0 | KiB/r 128 | KiB/w 0 | MBr/s 4.50 | MBw/s 0.00 | avio 1.28 ms |
DSK | sdd | busy 3% | read 29 | write 11 | KiB/r 111 | KiB/w 4 | MBr/s 1.58 | MBw/s 0.02 | avio 1.40 ms |
NET | transport | tcpi 40783 | tcpo 84348 | udpi 0 | udpo 0 | tcpao 22 | tcppo 39 | tcprs 553 | udpip 0 |
NET | network | ipi 40782 | ipo 14447 | ipfrw 0 | deliv 40784 | | | icmpi 0 | icmpo 0 |
NET | p262p1 ---- | pcki 40573 | pcko 84721 | si 9857 Kbps | so 502 Mbps | erri 0 | erro 0 | drpi 0 | drpo 0 |
NET | lo ---- | pcki 208 | pcko 208 | si 104 Kbps | so 104 Kbps | erri 0 | erro 0 | drpi 0 | drpo 0 |
```