Best posts made by flomer

Thank you!

I just registered after finding this site when searching for an article you have written... I was a little surprised seeing it was so easy to register. Nice!

Hello again, community!

I have used VMware for years now, but have avoided becoming an expert ;-). I have seen how good it is at consolidating many servers onto one host, effectively dealing out lots of RAM while not consuming all of it in real life. One of my servers now has about 220 GB as granted, but only 125 GB (of 128) actually used. That is good.
Now, I have been starting experienting With XenServer for several reasons. One of them being that an old server was not able to install current version of ESX, but XenServer 6.5 installed fine. The server is more than 7 years old, but has 32 cores and 64 GB RAM, so it is too good to let go. Also, after adding a couple of other old servers I am able to do live (storage) vmotion for free. This makes XenServer attractive.
But, now I run into memory trouble. The one server I will use as example has 64 GB RAM. One VM has been given 32 GB RAM, and another 24 GB RAM. Now, trying to power on a third VM With 8 GB RAM fails, because I have used up all the RAM... Hm. That was an unpleasant surprise. Does this mean that XenServer cannot "overcommit" memory like ESX can? Or is there a setting I can change?

Hm... After making sure XenTools is installed in all the VMs on the server, I can actually see the RAM being decreased for the already powered on VMs as I power on the last VM -- it works as expected now that all VMs have XenTools installed. Thanks!

Hello!

I have a DL380 G7 file server with FreeNAS 9.2. The data that is shared (CIFS, NFS) is on a RAID 6 made up of 6 x 3 TB MDL disks attached to a Smart Array p410i. Now, last week the disk started to get really slow. I had to shut down multiple VMs and move them off the server in order for my users to get to do any work. I had to move the VMs over nights several days in a row... The read rate of the drive was about 3 MB/s... All green lights blinking on the front of the machine. I was really puzzled... I wondered if perhaps the battery for the cache had stopped working. I have had no problems with this setup earlier (has been running for at least 10 months), but discovered now that FreeNAS/FreeBSD is not well supported by HP (or the other way around), so I could not get any info from inside FreeNAS. No software to inspect the status of the RAID. When all VMs and critical data was moved off of the server I could finally reboot it and run the HP SmartStart CD. I ran a short diagnostic test, and .... one of the drives was marked as Failed, due to too many read/write errors. Now, that explains it all. I replaced the disk, waited 12 (!) hours for the rebuild to finish, and now read/write is up to 250-400 MB/s. All is well.

So, the question remains (and I have sent this to my HP dealer);
Why was the drive not clearly (via the LEDs) marked as bad, and kicked from the RAID?

Has anyone ever seen this behaviour?

I live in Norway and it's getting late here. I will return to this thread tomorrow!

Dear community!
I have two old AMD servers, one with 8 Quad-Core AMD Opteron 8347 @ 1908 MHz and 64 GB RAM and the other one with 4 Quad-Core Opteron 8393 SE @ 3100 MHz and 32 GB RAM. I managed to add them to the same pool in XenServer 6.5, so I guess the CPUs are compatible (enough). I am curious as to what has been done in order to mask the differences between the CPUs. I live migrated a VM from one to the other (8347 to 8393), and I noticed that the VM was reporting the old clock speed for the CPU... Does this mean that the faster CPU of the second server will look to the VMs as having the same specs as the older 8347, or will this cahnge when I reboot the VM? Is it better from a performance point of view to keep the two servers separated, not in a pool?

Hm. So you are saying that a VM that is mirgated form the 1,9 GHz host to the 3,1 GHz host will actually run faster, even though it will not report the correct speed until a reboot? In that case it will be perfectly fine to pool the hosts together, for added flexibility and possible HA-fun

Well, it's on our lab network, and I am playing with and learning XenServer at the moment. I might move some of our production servers from vSphere to XenServer if things work out nicely.

Yes. At the moment we are having two different Essentials Plus environments, and I must say I am at times very frustrated about the limitations. I mean, why not 5 hosts instead of just three (6 CPUs)?? We are a rather small SMB-type department in a large organization, and I see that XenServer will give us things like live storage vmotion for free, whereas for vSphere I have to shut down the VMs... I am also playing with View, and thinking about virtualizing a few workstations that have powerful GPUs -- for that to work we need full licenses in order for vGPU to work, and this will be prohibitively expensive when we are just talking about 5 users... I feel sometimes that we are cought in the middle. We are a business, but have a small budget. Sigh...

@scottalanmiller I will try to investigate this and try to get in touch with our customer's IT dept. early in the process for our next project. It will be interesting to see what will happen. Already it is quite puzzling that most customers want us to deliver the hardware, rather than just providing a server to us, or ask us for a VM. I guess that should be an indication the the instrumentation part of offshore business is a little "special" when it comes to these things.

Well, it's not so simple for us. We usually have no remote support, and it's up to the customer's IT dept. to take care of things once the system leaves our premises. After commissioning we often don't even have admin rights. It's really puzzling, but we often feel that we abandon the systems once the customer takes over. Our company do have service personnel on the customer's site regularly, but that is for other tasks, and not to service our system. We have had cases where we have been told that "the machine beeps, it's been like that for 3 months"... I guess you could say that someone, somewhere has a job to do. I will try to investigate this when we get our next project. We are often a sub contractor, and we rarely speak to the end user or the IT staff supporting him in the early stages of a project.