[PVE-User] Very slow server (RAW IDE discs and KVM)

[Erik van Ast]

Hallo Holger,

Yes, when running no virtual machines, everything is at normal speed. Even when using the only the other (Windows 2008) machine, it seems fine. There is a major speeddrop when copying data over to the virtual server or within the virtual server. So when there is HD activity on the virtual server, it goes crazy...
I have also tested copying a lot of data over on the other virtual server (2008, on the same ProxMox server), but that works fine.
When copying many files over to the other (2008, VM106)) machine, this is the Atop output 

proxmox:~# atop
ATOP - proxmox            2011/08/10  14:09:12               10 seconds elapsed
PRC | sys   2.49s | user   3.45s | #proc    132 | #zombie    0 | #exit      0 |
CPU | sys     22% | user     35% | irq       3% | idle    283% | wait     58% |
cpu | sys      6% | user     14% | irq       1% | idle     47% | cpu000 w 32% |
cpu | sys      6% | user      7% | irq       1% | idle     61% | cpu001 w 24% |
cpu | sys      5% | user      8% | irq       0% | idle     86% | cpu003 w  0% |
cpu | sys      4% | user      6% | irq       0% | idle     88% | cpu002 w  1% |
CPL | avg1   0.60 | avg5    0.72 | avg15   0.50 | csw   109335 | intr   59490 |
MEM | tot    7.8G | free    2.2G | cache   1.9G | buff  249.0M | slab  145.3M |
SWP | tot    7.0G | free    7.0G |              | vmcom   3.3G | vmlim  10.9G |
DSK |         sda | busy     66% | read      26 | write    508 | avio   12 ms |
NET | transport   | tcpi     342 | tcpo     450 | udpi       0 | udpo       0 |
NET | network     | ipi      357 | ipo      450 | ipfrw      0 | deliv    346 |
NET | tap106 732% | pcki   34036 | pcko   62454 | si 1798 Kbps | so   73 Mbps |
NET | eth0     7% | pcki   60995 | pcko   33800 | si   71 Mbps | so 2448 Kbps |
NET | vmbr0  ---- | pcki     344 | pcko     406 | si   16 Kbps | so  567 Kbps |
NET | lo     ---- | pcki      44 | pcko      44 | si   13 Kbps | so   13 Kbps |

  PID  SYSCPU  USRCPU  VGROW  RGROW  RDDSK  WRDSK  ST EXC S  CPU CMD     1/1
 2382   2.47s   3.36s     0K     0K   248K 32236K  --   - S  57% kvm
 7099   0.01s   0.01s     0K     0K     0K     4K  --   - S   0% apache2
 7101   0.00s   0.02s   156K   112K     0K     0K  --   - S   0% apache2
 3179   0.00s   0.02s     0K     0K     0K     4K  --   - S   0% pvedaemon
 3194   0.00s   0.02s     0K     0K     0K     4K  --   - S   0% pvedaemon
 7058   0.01s   0.01s     0K     0K     0K     0K  --   - S   0% qm
 7047   0.00s   0.01s     0K     0K     0K     0K  --   - R   0% atop
 1955   0.00s   0.00s     0K     0K     0K     0K  --   - S   0% iscsid
    1   0.00s   0.00s     0K     0K     0K     0K  --   - S   0% init
   23   0.00s   0.00s     0K     0K     0K     0K  --   - S   0% sync_supers
   24   0.00s   0.00s     0K     0K     0K     0K  --   - S   0% bdi-default
  807   0.00s   0.00s     0K     0K     0K     4K  --   - S   0% kjournald
 1258   0.00s   0.00s     0K     0K     0K     0K  --   - S   0% edac-poller
 1882   0.00s   0.00s     0K     0K     0K     0K  --   - S   0% flush-254:2

DSK 66% is normal I think, and 73Mbps NET is also normal as I'm copying a lot of data over...

Met vriendelijke groet / Kind regards / Mit freundlichem Gruß,
Erik 

-----Oorspronkelijk bericht-----
Van: Holger Hampel | RA Consulting [mailto:h.hampel at rac.de] 
Verzonden: woensdag 10 augustus 2011 12:59
Aan: Erik van Ast
Onderwerp: AW: Re: Very slow server (RAW IDE discs and KVM) 

Hallo Erik,

PAG is found between SWP and DSK if one of the values is >0. Your SWP states all swap space free - so you don't have paging now.

Here is a DSK line from my laptop (standard sata disk):

DSK |  sda | busy   12% | read    0  | write   664 | KiB/r   0 | KiB/w   4 | MBr/s   0.00 | MBw/s   0.30  | avq  76.52 | avio 1.78 ms |

If you use the disk on the host (while no guest is running) - do you get normal speed?

Regards
Holger

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