Diggin' technology every day

September 10, 2009

Where is the serial console in ESXi

Filed under: Monitoring,Virtualization — Tags: , — Nate @ 8:28 am

Back to something more technical I suppose. I was kind of surprised and quite disappointed when vSphere was released with an ESXi that did not have serial console support. I can understand not having it in the first iteration but I think it’s been over a year since ESXi was first released and still no serial console support? I guess it shows how Microsoft-centric VMware has been(not forgetting that Windows 2003 introduced an emergency console on the serial port, though I haven’t known anyone that has used it).

Why serial console? Because it’s faster and easier to access. Most good servers have the ability to access a serial console over SSH, be it from HP, or Dell, or Rackable, probably IBM too. Last I checked Sun only supported telnet, not ssh, though that may of changed recently. A long time ago with HP iLO v1 HP allowed you to access the “VGA” console via SSH, using the remcons command, this vanished in iLO v2(unless they added it back in recently I haven’t had an iLO 2 system in about 1.5 years). If your dealing with a system that is several networks away, it is so much faster to get to the console with SSH then bouncing around with the web browser and fooling with browser plug ins to get to the VGA console.

Also serial console has the ability(in theory anyways) to log what you get on the serial console to a syslog or other kind of server(most console/terminal servers can do this) since it is all text. I haven’t yet seen a DRAC or an ILO that can do this that would be a nice feature to have.

ESX(non i) does support serial console though enabling it isn’t too straight forward, but at least it can be done.

Come on VMware for your next release of ESXi please add full serial console support, to be able to not only access the console while it’s booted but be able to install over serial console as well. Thanks in advance, not holding my breath!

August 19, 2009

Does size matter?

Filed under: Storage,Virtualization — Tags: , , — Nate @ 10:30 am

UPDATED – I’ve been a fan of VMware for what seems like more than a decade, still have my VMware 1.0.2 for Linux CD even. I just wanted to dispel a myth that ESXi has a small disk footprint. On VMware’s own site they mention the footprint being 32MB. I believe I saw another number in the ~75MB range or something at a vSphere launch event I attended a few months ago.

Not that it’s a big deal to me but it annoys me when companies spout bullshit like that. I just wanted to dispel the myth that ESXi has a small disk foot print. My storage array has thin provisoning technology and dedicates data in 16kB increments as it is written. So I can get a clear view on how big ESXi actually is.

And the number is: ~900 Megabytes for ESXi v4. I confronted a VMware rep on this number at that event I mentioned earlier and he brushed me off, saying the extra space was other required components not just the hypervisor. In the link above they compare against MS Hyper-V, they take MS’s “full stack” and perhaps compare it to their “hypervisor”(which by itself is unusuable, you need those other required components), hence my claim that their claim is a complete and totally bullshit number.

This is significantly smaller than the full ESX, which from the range of systems I have installed uses between 3-5 Gigabytes. When I was setting up the network installer for ESX I believe it required at least 25GB for vSphere, which is slightly more than ESX 3.5.  Again with the array technology despite me allocating 25GB worth of data to the volume, vSphere has only written between 3-5GB of it, so that is all that is used. But in both cases I get accurate representations of how much real space each system requires.

ESXi v3.5 was unable to boot directly from SAN so I can’t tell with the same level of accuracy how big it is, (“df” says about 200MB) but I can say that our ESXi v3.5 systems are installed on 1GB USB sticks, and the image I decompressed onto those USB sticks is 750MB(VMware-VMvisor-big-3.5.0_Update_4-153875.i386.dd), regardless, it’s FAR from 32MB or even 75MB, at best it’s 10x larger than what they claim.

So let this one rest VMWare, give it up, stop telling people ESXi has such a tiny disk footprint, because it’s NOT TRUE.

You can pry vmware from my cold dead hands, but I still want to dispel this myth on ESXi’s size.

UPDATED – I went back to my storage array again, and found something that didn’t make sense, it’s pretty heavily virtualized itself, but after consulting with the vendor it turns out the volume is in fact 900MB of written space, rather than 1.5GB that I originally posted, if you really want to know I could share the details but I don’t think that’s too important, and without knowing the terminology of their technology it wouldn’t make much sense to anyone anyways!

The first comment I got(thanks!) mentions a significant difference in size between the embedded version of ESXi and the installable(what I’m using). This could be where the confusion lies, I have not used any systems with the embedded ESXi yet(my company is mostly a Dell shop and they charge a significant premimum for the embedded ESXi and force you on a high end support contract so we decided to install it ourselves for free).

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