libvirt users - May 2014 - Re: [libvirt] Host OS, Storage Info

Hi,
Is there any way to get host OS information and host Storage in formations
using libvirt API...?
Rgds
-Sijo

Sijo,

*Pertaining to virt-manager and virsh sluggish behaviour after a clone
operation:*

Thanks for your response.

Honestly I do not know what "host Storage in formations using libvirt
API"
means.  Sorry.
I use virt-manager and virsh to do everything within KVM.  If there is
something better or
another product/app that will enable me to drill down into the system...let
me know...

However, perhaps this can help:

We are running *CentOS 6 (Update 5) 64 bit* - patched as of 11 April 2014.


I create the virtual machines with the virt-install command using the*
--file* switch and lay the system images of the vm's on the RAID5.
The RAID5 uses ext4.  The I/O to that volume is nice. We currently are
running twenty-six (26) VM's.  There is no I/O wait.  The system
has been up for thirteen (13) days.  The load index (top) is between 1 and
3.

Also, I have the following kernel tweak in /etc/sysctl.conf:

vm.drop_caches = 3

NOTE: Writing to this will cause the kernel to drop clean caches, dentries
and inodes from memory, causing that memory to become free;
           this helps to mitigate dipping into swap.

Thanks in advance for everything,

Tom



On Thu, May 22, 2014 at 2:46 AM, Sijo Jose <mailtosijojose@gmail.com>
wrote:
> Hi,
> Is there any way to get host OS information and host Storage in formations
> using libvirt API...?
> Rgds
> -Sijo
>
> _______________________________________________
> libvirt-users mailing list
> libvirt-users@redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users
>

On Thu, May 22, 2014 at 12:16:17PM +0530, Sijo Jose
wrote:
>Hi,
>Is there any way to get host OS information and host Storage in formations
>using libvirt API...?
>Rgds
>-Sijo
Check virsh help (most of the commands you probably want start with
'node' or 'vol'/'pool') or have a look at our hvsupport
page [1] for
virNode* and virStorage* functions.

If this isn't what you're looking for, specify your question in a
better way.

Martin

[1] http://libvirt.org/hvsupport.html

Martin, et al,

Sorry for the lag in response.

So I started playing with the various virsh commands.  Awesome.
Been doing some reading and I believe I have some things configured not so
well.
As I stated earlier in the thread, we have all of the VM image files on one
RAID5.  Very fast machine.

When using top, the load average is a stable "5.xx".  No I/O wait.
GB's of
free memory.  Swap has not been touched.
Using vmstat, I am writing to the RAID5 volume at a constant 150MB/s and
reading at a constant 275MB/s.

With all of that said, here are some results from virsh commands:

# virsh pool-list --all
Name                 State      Autostart
------------------------------------------------------
default              active     yes


# virsh pool-info default
Name:           default
UUID:            xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
State:          running
Persistent:     yes
Autostart:      yes
Capacity:       30.76 GiB
Allocation:     2.10 GiB
Available:      28.66 GiB


Now, is that ok to have all of the VM's using a default pool?
Or should a pool be created for each VM instance.
I honestly am not even sure what a pool references...?...

The more I read, the more I am moving away from thinking something in the
OS is the cause of my sluggishness.

Suggestions?

Many thanks in advance,

Tom






On Thu, May 22, 2014 at 9:16 AM, Martin Kletzander <mkletzan@redhat.com>
wrote:
> On Thu, May 22, 2014 at 12:16:17PM +0530, Sijo Jose wrote:
>
>> Hi,
>> Is there any way to get host OS information and host Storage in
formations
>> using libvirt API...?
>> Rgds
>> -Sijo
>>
>
> Check virsh help (most of the commands you probably want start with
> 'node' or 'vol'/'pool') or have a look at our
hvsupport page [1] for
> virNode* and virStorage* functions.
>
> If this isn't what you're looking for, specify your question in a
> better way.
>
> Martin
>
> [1] http://libvirt.org/hvsupport.html
>
> _______________________________________________
> libvirt-users mailing list
> libvirt-users@redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users
>