High memory usage & NFS slowness

luispt

New Member
Aug 5, 2010
22
0
1
Hello,

I'm testing proxmox and a few other alternatives ( xenserver, vmware ), in order to virtualize a few dedicated servers.

I setup a 2 machines cluster and a nfs storage ( in production will use a SAN and iscsi ). I have however a few problems:

3 Of created vms ( all kvm ), have almost all memory being used, one 3gb and other 1gb. Its a plain centos 5.5 install, so shouldnt be with this problem. What can cause this?

Regarding shared storage ( nfs ), i have slow speeds:

[root@localhost ~]# `dd if=/dev/zero of=/tmp/2G bs=1M count=2048; sync`
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 76.1599 seconds, 28.2 MB/s

Servers ( proxmox and nfs ) are connected to a switch at 1Ge. I should get better speed, no? How can i improve it?

Since i'm migrating from dedicated, i'm afraid that my customers will suffer a service degradation. Shared storage is a must, because of live migration and HA.

Also, another question ( maybe to many in a single thread? ).

Atm in my servers i have three nics ( internet, backend-backups and cdp ). The backend nic ( eth1 ) is used to make r1soft cdp backups. I plan to install this in kvm vms and do a daily snapshot of the VM to my cdp server. I cannot however use the internet nic, as i dont want to have both trafic together. How can i configure the KVM vm to use the second NIC of the server and another IP?

Sorry all this questions and thanks a lot for your time.
 
Your network cards are fully supported in the kernel you are using ?
I have a promox server with a Intel 82578DM (gibabyte ethernet) that only gets full speed in 2.6.32 kernel, in 2.6.18 the card it's used like a 10/100 Mbs nic.
 
3 Of created vms ( all kvm ), have almost all memory being used, one 3gb and other 1gb. Its a plain centos 5.5 install, so shouldnt be with this problem. What can cause this?

how do you messure memory usage?

Regarding shared storage ( nfs ), i have slow speeds:

What kind of NFS server do you use? What speed to you get normally?

How can i configure the KVM vm to use the second NIC of the server and another IP?

you can create a separate bridge using that second NIC. Then use that new bridge for the VM.
 
Last edited:
Hello,

Yes, nics are fully supported.

I'm seeing memory usage in proxmox ( vm details ), and in a top.

Since i'm only in tests, its a normal server c2d, with a 500gb drive. However if i copy a file from the nfs box to the proxmox host its much more faster.

Regarding the nic configuration, can you please tell me how to do that?

thanks a lot.
 
I'm seeing memory usage in proxmox ( vm details ), and in a top.

Most OS use all available memory for cache - so I guess that is quite normal.

Since i'm only in tests, its a normal server c2d, with a 500gb drive. However if i copy a file from the nfs box to the proxmox host its much more faster.

How large is the CPU load on the host during the 'dd' test? Does top show the kvm process using 100% CPU?
 
Hello,

O will check that and update the ticket quickly. Regarding the network part / NAT, that's very important, can you please provide more detailed information?
 
Ok, i was able to do it, thanks!

I have now eth0 - vmbr0 with my external IP and eth1 with a 10.11.0.X IP in each server.

Cluster use the external IP to connect, but i would like to create the cluster using the 10.11.0.X IP in order to get faster live migrations ( as its a 1Ge only for this and not for internet trafic ).

Is it possible to use the eth1 ips to connect the cluster?

thanks again for your great help
 
Still testing the solution. Is there any way to migrate from local storage to shared storage ( iscsi in the case )? How can i copy the vm?
 
Still testing the solution. Is there any way to migrate from local storage to shared storage ( iscsi in the case )? How can i copy the vm?

You currently need to create a volume on the iscsi storage first, and the use 'dd' to copy the data.
 
...or do a backup/restore to the new storage.
 

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