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Posts Tagged ‘Virtualisation’

First thoughts – VMware Fusion 3 vs Parallels Desktop v5

Posted by Preston on 2009-11-27

As an employee of an EMC partner, I periodically get access to nifty demos as VMs. Unfortunately these are usually heavily geared towards running within a VMware hosted environment, and rarely if ever port across to Parallels.

While this wasn’t previously an issue having an ESX server in my lab, I’ve slowly become less tolerant of noisy computers and so it’s been less desirable to have on – part of the reason why I went out and bought a Mac Pro. (Honestly, PC server manufacturers just don’t even try to make their systems quiet. How Dull.)

With the recent upgrade to Parallels v5 being a mixed bag (much better performance, Coherence broken for 3+ weeks whenever multiple monitors are attached), on Thursday I decided I’d had enough and felt it was time to start at least trying VMware Fusion. As I only have one VM on my Mac Book Pro, as opposed to 34 on my Mac Pro, I felt that testing Fusion out on my Mac Book Pro to start with would be a good idea.

[Edit 2009-12-08 – Parallels tech support came through, the solution is to decrease the amount of VRAM available to a virtual machine. Having more than 64MB of VRAM assigned in v5 currently prevents Parallels from entering Coherence mode.]

So, what are my thoughts of it so far after a day of running with it?

Advantages over Parallels Desktop:

  • VMware’s Unity feature in v3 isn’t broken (as opposed to Coherence with dual monitors currently being dead).
  • VMware’s Unity feature actually merges Coherence and Crystal without needing to just drop all barriers between the VM and the host.
  • VMware Fusion will happily install ESX as a guest machine.
  • (For the above reason, I suspect, though I’ve not yet had time to test, that I’ll be able to install all the other cool demos I’ve got sitting on a spare drive)
  • VMware’s Unity feature extends across multiple monitors in a way that doesn’t suck. Coherence, when it extends across multiple monitors, extends the Windows Task Bar across multiple monitors in the same position. This means that it can run across the middle of the secondary monitor, depending on how your monitors are layed out. (Maybe Coherence in v5 works better … oops, no, wait, it doesn’t work at all for multiple monitors so I can’t even begin to think that.)

Areas where Parallels kicks Fusion’s Butt:

  • Even under Parallels Desktop v4, Coherence mode was significantly faster than Unity. I’m talking seamless window movement in Coherence, with noticeable ghosting in Unity. It’s distracting and I can live with it, but it’s pretty shoddy.
  • For standard Linux and Windows guests, I’ve imported at least 30 different machines from VMware ESX and VMware Server hosted environments into Parallels Desktop. Not once did I have a problem with “standard” machines. I tried to use VMware’s import utility this morning on both a Windows 2003 guest and a Linux guest and both were completely unusable. The Windows 2003 guest went through a non-stop boot cycle where after 5 seconds or so of booting it would reset. The Linux guest wouldn’t even get past the LILO prompt. Bad VMware, very Bad.
  • When creating pre-allocated disks, Parallels is at least twice as fast as Fusion. Creating a pre-allocated 60GB disk this morning took almost an hour. That’s someone’s idea of a bad joke. Testing creating a few other drives all exhibited similarly terrible performance.
  • Interface (subjective): Parallels Desktop v5 is beautiful – it’s crisp and clean. VMware Fusion’s interface looks like it’s been cobbled together with sticks and duct tape.

Areas where Desktop Virtualisation continues to suck, no matter what product you use:

  • Why do I have to buy a server class virtualisation product to simulate turning the monitor off and putting the keyboard away? That’s not minimising the window, it’s called closing the window, and I should be able to do that regardless of what virtualisation software I’m running.
  • Why does the default for new drives remain splitting them in 2GB chunks? Honestly, I have no sympathy for anyone still running an OS old enough that it can’t (as the virtual machine host) support files bigger than 2GB. At least give me a preference to turn the damn behaviour off.

I’ll be continuing to trial Fusion for the next few weeks before I decide whether I want to transition my Mac Pro from Parallels Desktop to Fusion. The big factor will be whether I think the advantages of running more interesting operating systems (e.g., ESX) within the virtualisation system is worth the potential hassle of having to recreate all my VMs, given how terribly VMware’s Fusion import routine works…

[Edit 2009-12-08 – Parallels tech support came through, the solution is to decrease the amount of VRAM available to a virtual machine. Having more than 64MB of VRAM assigned in v5 currently prevents Parallels from entering Coherence mode.]

Posted in Aside, General thoughts | Tagged: , , | 11 Comments »

Nybbles

Posted by Preston on 2009-11-26

If you thought in the storage blogosphere that this week had seen the second coming, you’d be right. Well, the second coming of Drobo, that is. With new connectivity options and capacity for more drives, Drobo has had so many reviews this week I’ve struggled to find non-Drobo things to read at times. (That being said, the new versions do look nifty, and with my power bills shortly to cutover to have high on-peak costs and high “not quite on-peak” costs, one or two Drobos may just do the trick as far as reducing the high number of external drives I have at any given point in time.)

Tearing myself away from non-Drobo news, over at Going Virtual, Brian has an excellent overview of NetWorker v7.6 Virtualisation Features. (I’m starting to think that the main reason why I don’t get into VCBs much though is the ongoing limited support for anything other than Windows.)

At The Backup Blog, Scott asks the perennial question, Do You Need Backup? The answer, unsurprisingly is yes – that was a given. What remains depressing is that backup consultants such as Scott and myself still need to answer that question!

StorageZilla has started Parting Shot, a fairly rapid fire mini-blogging area with frequent updates that are often great to read, so it’s worth bookmarking and returning to it frequently.

Over at PenguinPunk, Dan has been having such a hard time with Mozy that it’s making me question my continued use of them – particularly when bandwidth in Australia is often index-locked to the price of gold. [Edit: Make that has convinced me to cancel my use of them, particularly in light of a couple of recent glitches I’ve had myself with it.]

Palm continues to demonstrate why it’s a dead company walking with the latest mobile backup scare coming from their department. I’d have prepared a blog entry about it, but I don’t like blogging about dead things.

Grumpy Storage asks for comments and feedback on storage LUN sizings and standards. I think a lot of it is governed by the question “how long is a piece of string”, but there are some interesting points regarding procurement and performance that are useful to have stuck in your head next time you go to bind a LUN or plan a SAN.

Finally, the Buzzword Compliance (aka “Yawn”) award goes to this quote from Lauren Whitehouse of the “Enterprise Strategy Group” that got quoted on half a zillion websites covering EMC’s release of Avamar v5:

“Data deduplicated on tape can expire at different rates — CommVault and [IBM] TSM have a pretty good handle on that,” she said. “EMC Avamar positions the feature for very long retention, but as far as a long-term repository, it would seem to be easy for them to implement a cloud connection for EMC Avamar, given their other products like Mozy, rather than the whole dedupe-on-tape thing.”

(That Lauren quote, for the record, came from Search Storage – but it reads the same pretty much anywhere you find it.)

Honestly, Cloud Cloud Cloud. Cloud Cloud Cloud Cloud Cloud. Look, there’s a product! Why doesn’t it have Cloud!? As you can tell, my Cloud Filter is getting a little strained these days.

Don’t even get me started on the crazy assumption that just because a company owns A and B they can merge A and B with the wave of a magic wand. Getting two disparate development teams to merge disparate code in a rush, rather than as a gradual evolution, is usually akin to seeing if you can merge a face and a brick together. Sure, it’ll work, but it won’t be pretty.

Posted in Aside, General thoughts | Tagged: , , , , , , , , , | Comments Off

Aside – Parallels Desktop 5 for Mac OS X

Posted by Preston on 2009-11-13

I’ve been using Parallels Desktop for the Mac for several years now – in fact, when I originally started using it, VMware were only talking about doing a desktop virtualisation product for the Mac.

That’s partly why I stay loyal to Parallels – they supported the platform sooner. The other reason is that after years of hearing tripe from VMware employees about why you couldn’t mix windows from both operating systems, Parallels went ahead and did it with Coherence. (Yes, VMware Fusion’s Unity functionality went there too, around the same time, but the amount of times I heard it wasn’t a feature they were interested in within Workstation, as an example, drove me nuts.)

So when Parallels Desktop v5 for the Mac came out, I jumped on the upgrade bandwagon. It’s given me one major positive – I can now run Solaris 10 AMD 64-bit on my Mac Pro; that was the one remaining OS I absolutely need to periodically run that I was being blocked from doing previously. After about 3 days of installing, reinstalling, downloading more recent versions of Solaris 10 AMD, I even finally managed to get networking operational within the VM too, which meant it was useful.

Other than that, Parallels v5 has been a bit of a disappointment. You see, currently for me, Coherence mode only works if I’ve got a single monitor attached to my machine. The only time that happens is when I’m using my laptop away from my desk, or when I’m traveling – and those are times I’m less likely to run VMs. Since Coherence doesn’t work for me 99% of the time, that means I can’t really try out the Crystal mode – though I’ll admit, I’m unlikely to use it heavily; I dislike the “shared apps” approach offered by Parallels, and the new Crystal view mode seems to rely heavily on this.

It does continue to annoy me that I don’t have the option of virtually turning the monitor off – why can’t I close the console for a running VM? Surely that’s not so huge a thing that it can only be limited to enterprise class virtualisation – aka ESX, VMware Server or Parallels Server. When you have 10+ VMs running at once, even minimised all those consoles start to get annoying.

While overall I’m pretty happy with Parallels performance in terms of memory and CPU, recent support cases have highlighted to me that when it comes to translated IO, Parallels struggles – it seems to peak at about 20MB/s per VM, regardless of the throughput capabilities of the attached device. I first noticed that under v4, and was unhappy to see no change in v5.

If you’re currently a Parallels Desktop for Mac user, and you haven’t yet upgraded, I’d suggest holding off until the next build of v5, rather than jumping into the initial build released. Hopefully by then they’ll at least have Coherence reliably working again.

[Edit, 2009-11-14]

I’d like to take back my comments about Parallels 5 still having mediocre IO performance. I just realised, a short while ago, that one of the VMs I’d been testing with had failed in its VMware Tools update. Now, with both VMs in this particular test config updated to Parallels Tools v5, instead of getting 14-17MB/s transfer speed between them as I’d been getting under Paralles v4, I’m now getting 45-57MB/s. Now that’s a performance improvement.

Posted in Aside | Tagged: , , , , , , | Comments Off

Virtualisation as an exercise in MTBF

Posted by Preston on 2009-11-08

When IT people discuss Mean Time Between Failure (MTBF), the most common focus is on disk drives. We all know the basics for instance – the more drives you put in an array, the lower the cumulative MTBF, etc.

What impact does virtualisation have on MTBF though? Are there any published studies? I suspect not yet.

I’ll be clear from the outset: I like virtualisation.

Just because I like it though doesn’t lead me to question how many sites (particularly smaller ones) implement it, and the risks that they carry of effectively decreased MTBF by putting too many eggs in one basket.

Consider for instance a small business that decides, as part of an infrastructure refresh, to replace their current fileserver, directory server, mail server, database server and internet gateway server with a single VMware ESX server. (We’ll assume of course that they do not virtualise their backup server – something you should never do.)

So, instead of having five primary production servers, each of which has some chance of experiencing a catastrophic failure, we now have one primary production server which can still experience catastrophic failure. I’m not talking at the OS layer here (though that’s still relevant), but at the hardware layer.

Let’s be honest with ourselves – this is IT, and things can go wrong in IT just as they can anywhere else.

Now, in a small business such as the above, it can be argued that the loss of any one server is likely to cause a fair to serious inconvenience, but in each case, other functions are likely to still be carried out while the hardware is being repaired. If people can’t email, they may be able to catch up on some documentation or file related work. If people can’t access the database, they may be able to process things manually while still emailing, etc.

If all five servers go down at once, that’s a significantly more challenging proposition.

Anyone with exposure to virtualisation, high availability/redundancy or data protection should see what is needed here – a second server, shared storage and the ability to have guest systems moved from one virtualisation server to the other. (In smaller companies it may be achieved instead by just having a standby server with storage that can be accessed by the other host if necessary.)

However, it’s clear there’s more to running a virtualised environment than just whacking a big server in and virtualising the hosts that are already in the computer room.

Companies that are now just starting to adopt virtualisation may feel that it’s a mature enough industry that the time is ripe for jumping in – and they’re right. In fact, it’s been mature enough for long enough that virtualisation is practically old hat.

Regardless of the maturity of virtualisation though, it doesn’t change the fact that you’re still at the mercy of hardware failures (or other critical virtualisation-host failures), and you still have to design your systems to provide the appropriate level of protection you can (a) afford and (b) is necessary. When doing cost comparisons, it’s not appropriate to compare say, the cost of replacing 5 servers with another 5 servers vs replacing 5 servers with 1 beefier server – virtualised services should never be about putting all the eggs in just one basket.

Without that consideration, it’s too easy to see MTBF for your computing environment fall through the floor – and blame virtualisation technology instead of the real culprit: the practical implementation.

Posted in Aside, General Technology, General thoughts | Tagged: , | Comments Off

Great VMware coverage

Posted by Preston on 2009-06-21

My colleague Brian Norris has been continuing his VMware coverage over at Going Virtual.

Recently he’s been doing a lot of work on securing ESX, integrating ESX into Active Directory, and experimenting with vSphere v4. If you’re interested in VMware and are looking for some tips and coverage from an expert, I’d suggest you keep an eye on his site.

Posted in Aside | Tagged: , | Comments Off

Things not to virtualise: backup servers and storage nodes

Posted by Preston on 2009-02-13

Introduction

When it comes to servers, I love virtualisation. No, not to the point where I’d want to marry virtualisation, but it is something I’m particularly keen about. I even use it at home – I’ve gone from 3 servers, one for databases, one as a fileserver, and one as an internet gateway down to one, thanks to VMware Server.

Done rightly, I think the average datacentre should be able to achieve somewhere in the order of 75% to 90% virtualisation. I’m not talking high performance computing environments – just your standard server farms. Indeed, having recently seen a demo for VMware’s Site Recovery Manager (SRM), and having participated in many site failover tests, I’ve become a bigger fan of the time and efficiency savings available through virtualisation.

That being said, I think backup servers fall into that special category of “servers that shouldn’t be virtualised”. In fact, I’d go so far as to say that even if every other machine in your server environment is virtual, your backup server still shouldn’t be a virtual machine.

There are two key reasons why I think having a virtualised backup server is a Really Bad Idea, and I’ll outline them below:

Dependency

In the event of a site disaster, your backup server should be at least equally the first server that is rebuilt. That is, you may start the process of getting equipment ready for restoration of data, but the backup server needs to be up and running in order to achieve data recovery.

If the backup server is configured as a guest within a virtual machine server, it’s hardly going to be the first machine to be configured is it? The virtual machine server will need to be built and configured first, then the backup server after this.

In this scenario, there is a dependency that results in the build of the backup server becoming a bottleneck to recovery.

I realise that we try to avoid scenarios where the entire datacentre needs to be rebuilt, but this still has to remain a factor in mind – what do you want to be spending time on when you need to recover everything?

Performance

Most enterprise class virtualisation systems offer the ability to set performance criteria on a per machine basis – that is, in addition to the basics you’d expect such as “this machine gets 1 CPU and 2GB of RAM”, you can also configure options such as limiting the number of MHz/GHz available to each presented CPU, or guaranteeing performance criteria.

Regardless though, when you’re a guest in a virtual environment, you’re still sharing resources. That might be memory, CPU, backplane performance, SAN paths, etc., but it’s still sharing.

That means at some point, you’re sharing performance. The backup server, which is trying to write data out to the backup medium (be that tape or disk), is potentially either competing with for, or at least sharing backplane throughput with the machines that is backing up.

This may not always make a tangible impact. However, debugging such an impact when it does occur becomes much more challenging. (For instance, in my book, I cover off some of the performance implications of having a lot of machines access storage from a single SAN, and how the performance of any one machine during backup is no longer affected just by that machine. The same non-trivial performance implications come into play when the backup server is virtual.)

In Summary

One way or the other, there’s a good reason why you shouldn’t virtualise your backup environment. It may be that for a small environment, the performance impact isn’t an issue and it seems logical to virtualise. However, if you are in a small environment, it’s likely that your failover to another site is likely to be a very manual process, in which case you’ll be far more likely to hit the dependency issue when it comes time for the full site recovery.

Equally, if you’re a large company that has a full failover site, then while the dependency issue may not be as much of a problem (due to say, replication, snapshots, etc.), there’s a very high chance that backup and recovery operations are very time critical, in which case the performance implications of having a backup server share resources with other machines will likely make a virtual backup server an unpalatable solution.

A final request

As someone who has done a lot of support, I’d make one special request if you do decide to virtualise your backup server*.

Please, please make sure that any time you log a support call with your service provider you let them know you’re running a virtual backup server. Please.


* Much as I’d like everyone to do as I suggest, I (a) recognise this would be a tad boring and (b) am unlikely at any point soon or in the future to become a world dictactor, and thus wouldn’t be able to issue such an edict anyway, not to mention (c) can occasionally be fallible.

Posted in General thoughts, NetWorker, Policies | Tagged: , , | 6 Comments »

 
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