ESX

VMware Vroom!

If you haven’t subscribed to this RSS Feed, you should do so now… it includes Performance Tips for ESX and vSphere. Here is the link and read the insert below.

“We made a huge number of performance improvements in vSphere 4.0. The ESX storage stack was no exception. We ran a wide variety of micro and real world benchmarks to thoroughly evaluate and optimize vSphere’s storage subsystem. It is now even more efficient for the enterprise and ready to support the cloud.

A wide variety of I/O intensive applications will run efficiently on vSphere with all the improvements.  You can find details on the architectural changes and storage performance improvements made in this white paper.”

I suggest you add the feed to your BlackBerries(Viigo) or iPhone immediately, yes now… not later, now.

NS

Understanding VMware Snapshots.

I wanted to clear the air on snapshots, everyone is always asking, how much space does it take to remove a snapshot, but no one has a real answer…  whatever the answer may be this information inserted from the Basic System Administration PDF, which is readily available from VMware and can be downloaded from this link here, will help to explain how they work, and what can be done if you run out of space and cannot commit a snapshot. Please take your time and read through the below information and you will get a much better understanding of snapshots. The information below is a copyright of VMware. I have in no way altered its content.

“The Understanding Snapshots section does not include information on delta disks. The section should contain the following content:

To take a snapshot, the state of the virtual disk at the time of taking the snapshot must be preserved. When this occurs, the guest operating system cannot write to the VMDK file. The delta disk is an additional VMDK file where the guest is given write access. The delta disk represents the difference between the current state of the virtual disk and the state at the time of the previous snapshot. If more than one snapshots exist, delta disks might represent the difference (or delta) between each snapshot. Also, the guest can write to every single block of the virtual disk causing the delta disk to grow as large as the base VMDK of the virtual machine.

NOTE To consolidate all snapshots into the base virtual machine, you might need extra disk space, as large as the base VMDK.

When a snapshot is deleted, if a user chooses to merge the changes between the snapshots to the previous disk‐state, all the data from the delta disk that contains the information about the deleted snapshot is written to the parent disk. This might involve a large amount of disk I/O and might reduce the virtual machine performance until consolidation is complete.

If the user chooses to ignore the delta disks, delta consolidation is not required.

See VMware Knowledge Base system for more information on the iterative snapshot deletion behaviour. I’ve Included the details of the (KB article 1003302).

Details

If you try to initiate a Delete All snapshot for a virtual machine using Snapshot Manager, and if that virtual machine is on a datastore that does not have sufficient space for the snapshot, the following message displays in VMware Infrastructure (VI) Client:

msg.hbacommon.outofspace: there is no more space for the redo log of <VMname>-0000xx.vmdk.

You are given the option to abort or retry.

• If you choose Abort, the virtual machine is powered off, the snapshot is aborted, and a Consolidate Helper snapshot is created. The Snapshot Manager UI displays that Consolidate Helper snapshot. You can delete the Consolidate Helper snapshot after you have made space available.
• If you click Retry, the Snapshot Manager returns to Consolidate Helper snapshot mode unless you have made more disk space available.

Solution

Free up disk space if possible, or extend the VMFS volume using VI Client.

To extend the VMFS volume:

1. Select the host on which the virtual machine resides and click the Configuration tab.
2. Select the datastore on which the virtual machine resides and click Properties.Note: If there is no available storage, a new LUN must be presented to every ESX host that can see the LUN.

3. In the dialog that appears, click Add Extent and follow the prompts in the Add Extend wizard to add an extent.
4. Perform a rescan on every ESX host that is being presented the new LUN so that the addition of the extent is detected.
5. After you have extended the VMFS volume, you can check the Retry option of the Redo log pop-up.

Caution: When using Delete All in the Snapshot Manager, the snapshot furthest from the base disk is committed to its parent, causing that parent snapshot to grow. When that commit is complete, that snapshot is removed and the process starts over on the newly updated snapshot to its parent. This continues until every snapshot has been committed. This can lead to an aggressive use of additional disk space if the snapshots are large. Use care when exercising this option if there is not much space available on the datastore.”

DRS, Vmotion, and Snapshots

I think setting DRS(Distributed Resource Scheduling) to manual mode when removing snapshots, should be best practice, especially when you are only running two ESX servers and they are slightly taxed. Why? Mainly because when you remove a snapshot, especially a two tiered one, it can cause the hard disk to “thrash” and thus signaling DRS to Vmotion a Virtual Machine from one ESX Server to the other ESX Server automatically. This will of course cause more stress on the hardware and eventually the client may notice the decrease in performance. Hey I’m just speaking from personal experience. When the snapshot is removed, re-enable DRS. Comments?

-NS

Windows XP and VMware ESX Server

Okay I have seen this a lot, and I have also solved this myself, but I’m going to be honest with you when installing Windows XP Pro on an ESX Server and using the LSI Drivers, you will have issues. There is a driver on LSI’s website that you can use, but I don’t have that information for you at the moment, I do however have another solution, using the BusLogic controller, you can utilize a flp image file that is already located on the datastore. Alot of websites say, use an LSI Logic controller and the floppy image and you will be fine, well thats wrong. This is in fact a virtual floppy for the BusLogic controller.

So basically, start the setup of Windows XP Pro whichever way you want, hit F6 and when it asks for the floppy, mount the flp file from the data store, connect it, then hit “S” to proceed. The BusLogic driver should load and you will then be able to proceed with the installation.

Also on a side note… if you decide to VMconvert Windows XP Pro you will not have any luck, I haven’t had a chance to experiment too much, but I think if you select BusLogic(on the VM Properties) on before conversion you might be Ok. If anyone can answer this for me that would be great. Last time I VMConverted a Windows XP box I was greeted with a lovely BSOD!

Here is a good reference link to check out if your having issues.

NS

VMWare Virtual Center Goodness

Well this isn’t about how much fun you can have with VMWare Virtual Center, but on how somethings can be worked around and some things just need to be re-installed!

Starts off with an couple ESX Servers and Virtual Center all running out of evaluation days… yes I know, procrastination on my part… and to top it off, my Virtual Center Server (which was a VM, and yes its a supported configuration) was off. When attempting to turn the server back on, the screen barked at me with a message stating that I did not have the proper licensing to do that. Well what does one do? You cheat How you say? Create a temporary license from your vmware login/manage licenses. Since the ESX Server is out of eval, you create yourself a nice little lic file and select host based licensing. Once you have the licensing in place you should be able to boot up virtual center. Once you have virtual center up and running, change all licensing to License Server-based Licensing. But be warned, if you let everything including Virtual Center Server run out of eval days, you may have to completely uninstall and reinstall VMWare Virtual Center, this includes SQL Server Express(if you chose to use it) Oh and before uninstalling SQL from Add/Remove Programs, remove “VMWare Update Manager” and “VMWare Virtual Center” from ODBC System DSN Tab.

How do I know all this? Spend 3 hours on the phone with a VMWare Licensing expert and a VMware Technical Engineer, and you will too!

NS

ESX 3.5, IDE, and Me

What the heck am I talking about you say? Well I decided to load ESX 3.5 on a workstation of mine. This is so I could do a test upgrade from 3.5 to 3.5 Patch 3, mainly because I want to make sure VMFS and the VMs are retained after upgrading to said patch level.

So I commenced installing ESX 3.5 on my 40GB IDE drive, yeah I said IDE, who uses those anymore anyways, apparently I do. The install went fine, for the most part, until it said that I wouldn’t be able to use the current drive as a datastore (without advanced configuration). Anyways on I go, I finish the install and all is fine. I was able to connect using Virtual Infrastructure Client, but then I see the message that ViC could not find any static storage, click here to configure a datastore. I clicked on the link and of course nothing was there… did some searching and it turns out that ESX 3.5 does not support IDE drives as a datastore due to the fact that NCQ(native command queuing) is missing from IDE Drive, however SATA drives will work fine. So what I ended up doing is I just installed a 80GB Sata drive, yes small i know, but its only for testing purposes, and rebooted the ESX machine, from ViC. Upon rebooting it found the new hardware and I was able to use ViC to add the new datastore… all 80GBs of it, all right!

Moral of the story… SATA/SCSI okay, IDE not okay

Till next time,

NS