vmware

vCenter Hardware Status Stops Polling After 1 Hour

by

(Update, 1/19/2012, 1130 CST: The product manager for this feature, commenting below, has indicated this is actually a bug, and I’ve emailed her the details of my case so she can help track down where the information I was told came from, and fix my problem, too) —————— For what seems like an eternity I’ve had a support case open with VMware because the hardware status functionality in vCenter (4.1 and 5) stops updating. I was told today by my support guy that, for a variety of reasons that cannot be known by me, VMware has decided that the hardware status polling should stop after 1 hour. So my bug isn’t a bug, it’s a feature, case closed. I am …

Read More

How Large Your Linux Swap Partition Should Be

by

This is post #4 in my December-long series on Linux VM performance tuning, Tuningmas. One of those timeless questions in system administration has always been “how much swap space do I configure on my server?” The old rule used to be twice the amount of memory, but does a server with 256 GB of RAM really need a half terabyte of swap? And what about VMs? Swapping on VMs is a serious performance drag. Would it be a good idea to just disable swap completely? One thing to consider is that there’s a tunable kernel parameter, /proc/sys/vm/swappiness, that controls the tendency of Linux to scavenge inactive memory pages and swap them out. It is a number from 0 to 100, …

Read More

Leave Some RAM For Filesystem Cache

by

This is post #3 in my December-long series on Linux VM performance tuning, Tuningmas. Many system administrators don’t realize it, but in most OSes RAM that’s unused by applications goes towards filesystem cache, which speeds disk operations. Some VM “right-sizing” tools don’t take this into account, and recommend pretty tight memory allocations which end up causing more disk I/O in the long term. Trading some RAM for better I/O performance is often a very good move, both for an individual VM and for the virtual environment as a whole. To understand what’s happening on a Linux VM and make a decision about how much RAM we should leave for filesystem cache we need to understand the ‘free’ command: total used …

Read More

Disable GUIs and X Windows on Linux VMs

by

This is post #2 in my December-long series on Linux VM performance tuning, Tuningmas. I remember an old story about people having performance issues on their Windows servers. It would happen intermittently, and never when the system administrator was around. Turns out it was the pretty OpenGL screensaver, which would kick in and slow everything down tremendously. When the admin was around he’d be using the console of the server, so no screen saver, and no problems. Graphical user interfaces make one-off administration tasks easier in some cases, but for virtual environments they come at a cost: additional RAM and CPU overhead. For a virtual environment you should shut them off, or install as little of them as you need, …

Read More

Align Your Partitions

by

This is post #1 in my December-long series on Linux VM performance tuning, Tuningmas. I wrote about it back in 2006, and lots of others have written about it since (Duncan Epping has a nice vendor-agnostic post with diagrams): misaligned storage trashing your I/O performance. What’s the big deal? In short, it is killing your I/O performance. Logical Block Addressing on your disk drive makes the Master Boot Record 63 bytes long. This means it occupies sectors 0-62 on disk, and the first partition will start at sector 63. The number 63 is a persona non grata in the computer world. It isn’t a power of 2, and it certainly doesn’t line up with your storage’s idea of the world …

Read More

Thoughts on the VMTN Subscription Idea

by

Mike Laverick has started something of a campaign to bring back the VMTN Subscription, which was something like the Microsoft TechNet or MSDN models. I’m a TechNet subscriber and for $349 I get access to most everything Microsoft has. For testing purposes this is great. I don’t have to spend a lot of time dealing with activation timeouts, I can just test things and leave the my own test environment up and running for when I want to test new VMware Tools, or whatever. I think that’s fair, since I buy real Windows licenses for every other VM that I have (dev, test, QA, production, etc.). Right now, if you want a test environment your options are to pay for …

Read More

Why Does My Linux VM's Virtual NIC Show Up As eth1?

by

Got a Red Hat Enterprise Linux (or CentOS, or Scientific Linux, or Oracle Enterprise Linux, etc.) 6 VM that won’t bring up it’s single network interface after you clone it? Get the following error when you try using /sbin/ifup to enable it? “Device eth0 does not seem to be present, delaying initialization.” When you use “/sbin/ifconfig -a” you see eth1 where eth0 should be? eth1      Link encap:Ethernet  HWaddr 00:50:56:9B:00:85             BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:812 errors:0 dropped:0 overruns:0 frame:0           TX packets:214 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:72509 (70.8 KiB)  TX bytes:28324 (27.6 KiB) lo        Link encap:Local Loopback            inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:16436  Metric:1           …

Read More

How to Install Microsoft SQL Server 2008 R2 for VMware vCenter 5

by

My venerable post on installing MS SQL Server 2008 for vCenter 4 was getting old, so I thought I’d update it, if only because I have a new admin helping me and I’m going to stick him with doing a bunch of installs. Ha! I thank the VMware folks who have incorporated a lot of the tweaks from my original document into the defaults for vCenter 5. They were probably obvious, and not taken from my work, but it’s content I don’t need anymore. Awesome. While I don’t mean this page to become a general support site for vCenter SQL Server installations please leave a comment if something needs to be clarified or corrected, or if I’m doing something dumb …

Read More

Yak Shaving

by

One of my favorite terms for my day-to-day work life is “yak shaving,” and I’m saddened that so many people have not heard of it when I say it. “What are you doing today?” I’m asked. “Shaving yaks,” I reply. Coined at MIT as part of the Computer Science and Artificial Intelligence Lab (CSAIL), it’s described well in Jeremy Brown’s archived email: You see, yak shaving is what you are doing when you’re doing some stupid, fiddly little task that bears no obvious relationship to what you’re supposed to be working on, but yet a chain of twelve causal relations links what you’re doing to the original meta-task. Similarly, the Jargon File has it as: Any seemingly pointless activity which …

Read More

8 Things I Really Like About VMware Workstation 8

by

I’ve been using VMware Workstation 8 for a few days now. I really like it. A lot of posts have been made hitting some of the major highlights, but there are hundreds of small improvements that add up to be a big deal for me. Here are eight. 1. You can connect to a vSphere setup, and upload your VMs into the server environment. I’ve already used it to set up a new VM template locally, then upload it to my production environment. As I get more into vCloud Director I anticipate using this heavily to set up templates for new (or old) OSes. It’ll also be a great solution for dealing with virtual appliances that make assumptions, like DHCP. …

Read More

+ More Posts +