Switched On Tech Design

Author: sotech

XenServer 6.2: How to boot a VM to CD/DVD rather than disk

We had a situation recently where a customer was experimenting with XenServer 6.2 and Ubuntu VMs; he accidentally powered off the VM during a distribution upgrade and the VM would only boot with a read-only filesystem. Loading an ISO into the virtual CD drive didn’t do the trick; there’s no obvious way of booting to another medium during the boot process.

The trick is to boot into recovery mode; when the VM is powered off, select it and follow the menus like so:

VM -> Start/Shutdown -> Start in Recovery Mode

The VM should now boot to your Live CD/Rescue CD/etc.

August 27, 2013
Western Digital Se 2TB (WD2000F9YZ) Hard Drive Review

Today we are looking at a new line of drives from Western Digital – the Se range. Click through to read our review of the baby of the new line – a 2TB drive…

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August 25, 2013
HP ProCurve 2510-24 Power Consumption

We measured the ProCurve 2510-24’s power usage:

Idle: 11.9W

Peak: 14.8W

This was measured on a 240V power circuit with a handful of devices attached (5). The peak wattage was measured during power-on and idle was steady around 11.9W. We would expect power usage to increase as you add more bandwidth-heavy devices; however, now that many of these switches are falling into the hands of home enthusiasts for connecting things like low-bandwidth computers, printers, Raspberry Pis and the like it should stay quite a low figure even with more devices connected.

So, how much does it cost to run? Assuming the minimum power draw is 12W and that electricity costs ~$0.30/KWhr:

Weekly: 2.016KWhr; $0.60

Monthly: 8.064KWhr; $2.42

Annually: 104.832KWhr; $31.45

All up it’s not a particularly expensive device to keep running. If you don’t need gigabit speeds this switch can be an excellent choice for getting a large number of devices onto the same network – 100Mbit is more than enough for browsing, light file sharing and streaming, printing, 100Mbit devices like Raspberry Pis and more.

August 7, 2013
How to install XenServer 6.2 – Step By Step

With the recent public availability of XenServer 6.2 there are an increasing number of people wanting to try it; here is a walk-through of an install so that you know what to expect if you want to try it yourself. In this example we are using a NFS datastore on the network to store VM files. First, burn the ISO installer to a CD and boot to it:

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August 6, 2013
How to install an Asus PIKE 2008 card

As a non-standard PCI-Express card, the Asus PIKE card involves a slightly different installation procedure.

The PIKE slot sits on either side of a gap in the motherboard:

You’re definitely not going to mistake it for a regular PCI-Express slot. The card only goes in one way, with the heatsink facing the PCI slots; it can be a little hard to get in sometimes as it needs to be inserted from almost directly above.

Motherboard-side view:

The card is secured on either end; on the side closest to the SAS/SATA ports, it hooks under a latch on the slot:

Here you can see the metal part of the PIKE card latching underneath the slot’s edge. You can also see how close other board components often are to this end! The other end sits over one of the motherboard mounting holes:

Don’t install the card without taking this screw out first, otherwise you’ll be taking it out and starting over. Now the card will activate the SAS/SATA ports next to it:

Easy done! Taking the card back out can be a little challenging with the metal clip on the side where the ports are, particularly if you have PCI cards still installed while you try to remove it (e.g. when the motherboard is still in the chassis). On the topic of removing the card while the motherboard is still in the chassis – as the card is quite short and the insertion pressure is reasonable so it’s quite difficult to remove in the chassis if there’s not a lot of space on both sides. A better idea is usually to take the motherboard out in these cases to minimise the risk of damage to the card or other board components.

You can buy the Asus PIKE 2008 card from Amazon.com:

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July 23, 2013
Asus PIKE 2008 card review

Many storage enthusiasts are familiar with the IBM M1015 card, an IBM rebadge of the LSI 9220-8i host bus adapter (HBA), based on LSI’s SAS2008 chipset. Less are familiar with Asus’ PIKE card – essentially the same thing in Asus’ own form factor, fitting only their proprietary PIKE slots.

This card activates the onboard eight 6gb/s SAS/SATA ports featured on server boards with PIKE slots. The straight 2008 model acts just like an M1015 in IT mode; the IMR model gives you RAID capabilities, namely RAID1/RAID10/RAID0/RAID1E.

The card itself is quite small, fitting into 1U chassis’ – at a mere 1.57″ high and 6.44″ long, it’s quite a bit lower than your usual PCI-E cards. Operating system support for the SAS2008 chipset is excellente – it has worked out of the box with every modern OS and hypervisor we have tried recently (e.g. Windows 7, Ubuntu 10.04-12.04-13.04, OpenIndiana, ESXi 4+ etc.).

The card itself is readily available, at least in the US and AU – at around $130/140 new it’s actually extremely reasonably priced vs. picking up a used M1015 on eBay. With a PIKE card you’ll get a warranty, make use of an otherwise-unusable slot and keep one of your PCI-E slots free for other uses, so there are quite a few reasons to consider one.

One caveat exists, primarily affecting those attaching a number of SSDs to the controller. Not all Asus motherboards have the same electrical connectors to the PIKE slot – some are PCI-E 2.0 x4, some PCI-E 2.0 x8, some PCI-E 3.0 x8 – there may be other combinations but these are the ones we have tested so far. A x4 connector may bottleneck a number of SSDs in use simultaneously; it’s extremely unlikely that you’ll hit that limit with spinning disks. It’s worth being aware of what electrical connection is present to you PIKE slot if you ever intend on hooking up a lot of fast drives as you may end up unintentionally bottlenecking their performance.

In terms of performance, it acts exactly the same as plugging in an IT-mode M1015; eight extra ports are activated without fuss and drives hooked up to those ports should appear immediately in your OS. lspci should show something along the lines of:

03:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon] (rev 03)

Super straight-forward – couldn’t be easier. The card supports hot-swapping, too.

The PIKE card is well worth a look in as an alternative to a secondhand M1015/LSI card for those enthusiasts with an Asus board with a PIKE slot.

Also see: How to install a PIKE 2008 card

You can buy the Asus PIKE 2008 card from Amazon.com:

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July 22, 2013
Ubuntu Forums hacked, passwords + emails taken – change yours if you are a user!

On the 20th July (US time) the Ubuntu forums were hacked and local usernames, email addresses and passwords were taken. The passwords aren’t in plaintext but regardless, change yours if you are/were a user!

July 21, 2013
Asus P9D-E/4L – Clearance between PIKE and PCI slots

One potential caveat of utilising the PIKE slot is that there is minimal clearance between the PIKE card heatsink and the nearest PCI slot; once the card is installed;

Mere millimeters! A top view:

This poses two problems. Firstly, not many PCI cards have low enough clearance to actually fit! We tried to fit a number of cards – NICs, USB cards and serial port cards – and the vast majority were unusable due to the low clearance. We did have success with an Astrotek USB 2.0 expansion card – just.

Secondly, if you do have a card that has short enough components that it doesn’t hit the PIKE card you will significantly reduce the amount of airflow available to the PIKE card. Depending on how your case is set up for airflow, this may be cause for concern.

Given that this board has plenty of PCI-E expansion and a second PCI slot, this is unlikely to be a significant issue for most people – but it is worth knowing about in case you do intend on using both PCI slots and the PIKE slot at once.

July 21, 2013
Asus P9D-E/4L Haswell Server Motherboard Review

With the recent release of Intel’s Haswell architecture came new server boards to match. From Asus came the new P9D line, and within that line the Asus P9D-E4/L is the flagship model with quite a comprehensive list of features.

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July 9, 2013
XenServer 6.2: NICs showing as disconnected despite being connected

Sometimes if you connect a network cable to a NIC XenServer doesn’t register it and keeps the status as disconnected; if this happens, try the following via SSH (or from the console, though you will be kicked out of XenCenter once you do it):

xe-toolstack-restart

It may take a little while for the restart to finish but once it does the NIC should be showing the correct status.

July 9, 2013