VM's going really slow after 3 - 4 weeks

tjkreidl

@Gheppy You have to give dom0 enough CPU power for various reaasons: 1) to be able to not be bogged down, itself, 2) to allow VMs to be able to interact with dom0 reasonably fast, 3) to provide enough resources to deal with storage and network I/O. Showing essentially no swap space in use is good!

Berrick

Seasons greetings to all,

So the slowness of is creeping back. Still cant find any thing obvious
Latest Xen Top

Due to business pressures we have had to reboot the physical server.
So now have to wait for the issue to re occur.

there were 5 more patch's which have been applied.

If anyone has any other suggestion of what to check, specific logs to search etc, etc they would be gratefully received

Kind regards

olivierlambert

Adding @fohdeesha in the loop

Tristis Oris

can't say that time from reboot a cause of problem, but sometimes i'm feel something about it. Even ssh connection takes tooooo long, like 10 sec in local network. Same for http speed for small services without any load.

tjkreidl

@Berrick Run iostat and see if anything shows up as slow or saturated with your storage I/O.

EddieCh08666741

hi Berrick, most of the issues that happen like this is due to IO i believe. I've been using XCP ng for many years and I have about 100 VMs. I love xcp and its the best out there. There are few instance that my VM starts to crawl to be unusable.

One of the disk fails in the raid and cause my VMs on that particular server to crawl.
Too little memory provisioned. Heavy usage.

Hope my above helps

tjkreidl

@EddieCh08666741 Indeed. Run top and make sure you have adequate resources allocated for dom0 for both memory and CPU. There should be no swapping to speak of and the CPU should be nowhere close to 100% in use.

Berrick

Thanks for all the replies.
I will be checking when the issue starts again in a few weeks and report back.

From previous xentop output I don't believe Dom0 is showing high CPU or Memory.

I also dont think there is a problem with the physical disks.

Berrick

@Berrick
So its been a while since my last post on this topic but finally I think we have bottomed this issue out!

So the long and the short.
Nothing we tried, checked or diagnostics ran up to this point showed any issue.
Then one Monday morning there was one alert from the iLO about "Corrected Memory Error threshold exceeded"

As this server was due a memory upgrade to LV memory soon and we would need to reboot to clear the alert we brought the upgrade forward.

Since the new memory was installed, tempting fate here, it has been OK

Thanks to all that offered advice.

Kind regards

olivierlambert

Oh wow. So something was wrong with the hardware, specifically the memory, and potentially more errors and error correction trying to keep up, slowing down everything. Is it a good recap?

Berrick

@olivierlambert said in VM's going really slow after 3 - 4 weeks:

Oh wow. So something was wrong with the hardware, specifically the memory, and potentially more errors and error correction trying to keep up, slowing down everything. Is it a good recap?

To be honest I am not entirely sure.
I tested the memory my self in the early stages of this issue with memtest. In the past memtest has flagged memory issue that HP built in diags hasn't but it ran clean.

The server was rebooted prior to replacing the memory out of curiosity and everything came up OK no errors.

So we assume that something was wrong with the memory. And now we have are fingers crossed that that is the end if it