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Saturday, April 18, 2015

Xenserver 6.2 to 6.5 upgrade notes

With 6.5 released we have started upgrading machines. Our initial upgrades were fairly straightforward and although the install of the Xentools was very slow and required numerous restarts it completed fairly well.

We have had issues with 2012 server running Exchange 2013 - insofar that we've lost the network adapter and can't get it back. The solution seems to have been to clone the VM and then remove and add the adaptor back in. The restart took a very long time and there were issues with the Xentools install not working properly and difficulties with getting it to upgrade. We ended up removing it and reinstalling it however that wasn't really optimal and we blew our outage window but quite a margin.

Before upgrading Xentools definitely take a snapshot of the VM if it's running Exchange. As we do more I will continue to update this site with more information.

Sunday, April 5, 2015

Things to remember - Google Sheets - how to show the last number in a column

I have a Google Sheets file that I put all the water information for our farm into. It's fairly comprehensive with formulas etc to let me know the following once I measure the water level from the top of the tanks:

  • volume of water remaining
  • amount used since the last recording date
  • average usage since last recording date
  • amount of rain we can have until the main collection tank overflows (so I know when to pump it up to the feeder tanks)
I would like a summary of the actual levels in each tank in a nice little chart that I can import into our personal intranet site hosted with Google Sites (this part is ridiculously easy), but I don't want to have to change the site information overtime I think about it. 

I found this:

=FILTER( A10:A100 , ROW(A10:A100) =MAX( FILTER( ArrayFormula(ROW(A10:A100)) , NOT(ISBLANK(A10:A100)))))
Now if you put that into a cell, alter the ranges to suit, it will give you the last number in the column (and maybe row, but I haven't tested that). It works very well - not only for numbers but for the dates as well. The little summary chart now shows:
  • The Date of last reading
  • amount of water remaining in each tank
  • amount of rain we can store until the collection tank overflows
And with Google Sheets adding in some decent conditional formatting I have it all colour coded and it looks a bit like this:


Not bad eh? The bit that tells me the overflow is elsewhere on the page. And yes, we're in pretty decent shape given that it's the start of Autumn and we should get rain soon!

Monday, February 23, 2015

Service - what does it mean to you?

Recently our little company has been very busy and while it has been tricky to maintain a high level of service, it's something we are managing very carefully. Interestingly though, we have had clients ask us to do things quickly, easily or cheaply. Generally there is no difference in the service provided, however, as our time becomes more precious, it's easy to take the client's request and act on it in the manner they have requested.

For example - "Can you quickly wipe these computers and then roll them out to be sold?"

"Sure - how much time and effort do you want us to put in to this?" (read: how much money do you want to spend on using our valuable time).

"Not much, just make sure our data's wiped and then get them out the door."

OK, so we clear the data, wipe the free space or re-install after a Darik's Boot And Nuke (DBAN) and then roll them out.

Now our client says to us that it hasn't been done properly and they want an explanation. For the first time ever, I reckon, I pointed at the email trail and said to them "You wanted fast, easy and cheap. You got it. If you want well done, comprehensive and completely satisfying, that does not fall into the fast/easy/cheap categories".

Interestingly the client sat back for a moment, said "You've got a point there. Can you sort this out properly?" Well sure I can and I have, but the cost in my time is there.

There's a line in the movie Tango and Cash where Jack Palance replies to two of his underlings telling them "Quick and Easy. Quick and Easy is how you make a cake." and then goes on to talk about killing Tango and Cash. My point to the client today was "Quick and Easy is how you make a cake - not have a well thought, solid and reliable IT infrastructure." Wake up peeps - spend some money and do it right the first time and stop being disappointed when you pay minimal dollar and get minimal effort.

Thursday, January 8, 2015

XenServer 6.2 update woes

Recently I was required to update a number of XenServers that I've taken over. They were running 6.2SP1 but were about 6 updates behind. No problem, I'll just queue the updates up and shoot them over. Had 2 Windows VM's (2008R2 and 2012 server) and 5 Ubuntu 12.04LTS Linux Servers. The updates were fairly straight forward - I followed my own guide :-)

After the final update was completed I booted up the VMs only to find the two Windows Servers came up no problems, and none of the Linux servers booted. None of them. They started up, black screen and white cursor in the top left hand corner and that was it. No boot no errors, just gone.

I ran through some basic repair work and had no joy. I changed the GrubConf.py from if arg.strip() == "${saved_entry}": to if arg.strip() == "${saved_entry}" or arg.strip() == "${next_entry}":. Still no luck. I re-installed Grub - no joy. I booted from the Ubuntu server CD and tried to run rescue the broken install. On several of the VM's I couldn't even get the system to run a shell in the / file system (/dev/xvda1 typically on these setups). It was incredibly frustrating and after three weeks of banging my head against this, I've still not managed to get this all going.

Luckily I had backups of most of the servers and so I haven't lost everything but I have lost some critical data. The message here, dear friends, is multiple:

  • test the updates one at a time to make sure everything starts up. Yes it will take longer and it's a bit more frustrating, but believe me, you want to know if things are going to shit themselves.
  • backups backups backups - are not important. RESTORES! are the important part. Believe me, I cried into my beer when I couldn't get one of these machines back up and going - it just wasn't going to happen. I lost a wiki with data that wasn't anywhere else and that's caused me no end of grief. The extra work it's caused is phenomenal and I feel very bad about it indeed.
I've reached out to the collective wisdom of SAGE-AU (www.sage-au.org.au) but sadly no luck yet. I'm open to suggestions!

elementary OS Review

I came across elementary OS on LifeHacker I think and thought it looked pretty interesting. I've been looking for a lightweight operating system that's reliable and fairly full featured (I accept it won't be totally featured - that's the cost of lightweight) for use on various older laptops and the like.

elementary OS is a free download with donations as optional. I downloaded it and burned it to a CD. Alas my favourite test laptop has gone the way of the dodo and is never to return (much like the dodo). I found a HP Pavilion D6 floating around, replaced the hard disk (it was toast) and the RAM (also toast) with 6GB. It's an i3 which doesn't really qualify as a lower end machine, but what the hey.

elementary is based on Ubuntu linux and is quite heavily customised running a lightweight desktop called Pantheon. The current version of elementary is called Luna and it's nice to see they are in development of new versions and it seems like an active development environment. Midori is available for Internet access - I installed Chromium as that's my preferred web browser. There is a calendar app, Geary Mail (which I haven't used), Shotwell for photo organisation and Empathy to tie in with Jabber, Facebook etc.

The interface is slick and looks good and the laptop boots a rocket. All the apps are fast and updates etc are easy as pie. There is an application for updates which is simple and straightforward and the whole thing is well organised and designed. It's quite a joy to use actually. The application install package - Software Center - looks good and is straightforward to use, offering a large range of packages. All the stuff I like to use I was able to install and get on with the job. I have a pretty small requirement list though, in the interests of full disclosure. Chromium has to work, I have to be able to burn CDs and DVD's and I need terminal to be fully functional. Pretty, fast and stable are the other three musts for any OS and I find elementary to check all those boxed.

I now run Mint and elementary side by side on laptops and desktops - the speed difference is quite noticeably between the two, and with their ultra stable Ubuntu (Debian) ancestry it's lovely to use. I've enjoyed using elementary OS Luna and I'll be keeping it on my Pavilion for the future - well as long as the Pavilion holds together!

Sunday, November 2, 2014

Google Sheets - inserting a static variable

Ever had a spreadsheet with set variables and wanted to use them in a formula but not have to type them over and over - just use the drag down feature and have it work? For example, if I had a formula where I wanted A3 to be present as part of it, and when I try to apply that formula to multiple cells the A3 becomes A4, A5, A6 etc? That's very annoying and up until now I've gone through and manually corrected it.

Not any more! By putting a $ sign in front of the column ID and the row ID e.g. $A$3 - it won't change! It stays the same! OMGWTFBBQ!

How long have I looked for this - I found the answer here: http://www.gcflearnfree.org/googlespreadsheets/14.3 - read up for more info! Yay!

Wednesday, September 24, 2014

How to restore a file with StorageCraft ShadowProtect

I've installed ShadowProtect on most of my clients' servers - it's a great product and if you're not using it for backups, then seriously consider it. One of our sub-contractors emailed me with some issues on restoring files so I thought I'd add my reply to him here as a quick cheat sheet:

  • Log onto the server you need to restore the file from
  • Open up the share where your backups are going
  • Browse through the list of files and look for an .cd or .cw or .cm file around the correct date
    • -cd.spi is a consolidated daily
    • -cw.spi is a consolidated weekly
    • -cm.spi is a consolidated monthly
    • for a full listing see here: http://bit.ly/1mNLBps
  • once you've found the correct file, right click on it and choose ShadowProtect Mount
  • pick the defaults, except when it comes to the right date - the consolidated files have a list of possible days / weeks that you can choose - find the right one and click on it, then go Next
  • mount the file as read-only unless you need read-write access
  • the computer will mount the drive as a new drive letter
  • browse through that drive until you find the file you want to restore, then copy and paste it to the right location and that's it
  • unmount the backup image and all finished! 

It's important to note this is only one of two ways of doing it. You can use the wizard that is part of ShadowProtect and it's even easier. At the time I was in a hurry and had to find multiple awful files so I used this method, plus I find that I use this method for Granular Recovery for Exchange restores.