Fixing Two Small DELL Compellent Hardware Hiccups


Here’s two little tips to solve some small hardware issues you might run into with a Compellent SAN. But first, you’re never on your own with CoPilot support. They are just one phone call away so I suggest if you see these to minor issues you give them a call. I speak from experience that CoPilot rocks. They are really good and go the extra mile. Best storage support I have ever experienced.

Notes

  • Always notify CoPilot as they will see the alerts come in and will contact you for sure Smile. Afterwards they’ll almost certainly will do a quick health check for you. But even better during the entire process they keep an eye on things to make sure you SAN is doing just fine. And if you feel you’d like them to tackle this, they will send out an engineer I’m sure.
  • Note that we’re talking about the SC40 controllers & disk bays here. The newer genuine DELL hardware is better than the super micro ones.

The audible alert without any issues what so ever

We kept getting an audible alert after we had long solved any issues on one of the SANs. The system had been checked a couple of times and everything was in perfect working order. Except for that audible alarm that just didn’t want to quit. A low priority issue I know but every time we walk into the data center we were going “oh oh” for a false alert. That’s not the kind of conditioning you want. Alerts are only to be made when needed and than they do need to be acted upon!

Working on this with CoPilot support we got rid of it by reseating the upper I/O module. You can do this on the fly – without pulling SAS-cables out or so, they are redundant, as long as you do it one by one and the cabling is done right (they can verify that remotely for you if needed).

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But we got lucky after the first one. After the “Swap Clear” was requested  every warning condition was cleared and we got rid of the audible alert beep!  Copilot was on the line with us and made sure all paths are up and running so no bad things could happen. That’s what you have a copilot for.

Front panel display dimming out on a Compellent Disk Bay

We have multiple Compellent SANs and on one of those we had a disk bay with a info panel that didn’t light up anymore. A silly issue but an annoying one as this one also show you the disk bay ID.

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Do we really replace the disk bay to solve this one? As that light had come on and of a couple of time it could just be a bad contact so my colleague decided to take a look. First  he removed the protective cover and then, using some short & curved screw drivers, he took of the body part. The red arrow indicates the little latch that holds the small ribbon cable in place.

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That was standing right open. After locking that down the info appeared again on the panel. The covers was screwed on again and voila. Solved.

TechNet Top Support Solutions From Microsoft Support Blog


As this year comes to an end I’d like to draw your attention to Microsoft’s new Top Support Solutions blog on TechNet. It was created this as part of their continuous efforts to keep the various  technical communities informed about the most relevant answers to the top questions or issues experienced with their products. They identify these top issues by analyzing the question in their forums and their other support channels.

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So if you need to find answers for your self or your customers go take a look at the "Top Solutions Content" blog. Changes are you’ll find valuable information about the Microsoft top support solutions for several of their popular products in Server and Tools. It might save you and your clients or manager a lot of time, effort and money. It’s also a great resource to make your colleagues, community, user group or clients aware of.

DELL Server DRAC Card Soft Reset With Racadmin


Sometimes a DRAC goes BOINK

Sometimes a DRAC (Dell Remote Access Card) can give you issues. Sometimes it’s some lingering process or another hiccup that causes this. You can try a reboot but that doesn’t always fix the issue. You can go into the BIOS and cancel any running System Services. A “confused” DRAC card can also be fixed by shutting down the server and cutting power for 5 to 10 minutes. That’s good to know as a last resort but not very feasible a lot of times, bar a maintenance window when you’re on premise.

You can also try to do a local or a remote reset of the DRAC card via OpenManage  (OMSA), racadmin. See RACADM Command Line Interface for DRAC for more information on how and when to use this tool. The racadmin can be used for a lot of remote configuration and administration and one of those is a “soft reset” or basically a powercycle, aka reboot, of the drac card itself. Don’t worry your server stays up Smile.

Local: racadmin racreset soft

Remote: racadm -r <ip address> -u <username> -p <password> racreset soft

Real life example

I was doing routine maintenance on 4 Hyper-V clusters and as part of that DUPs (Dell update packages) were being deployed to upgrade some firmware. This can be automated nicely via Cluster Aware Updating and the logging option will help you pin point the issue. See http://workinghardinit.wordpress.com/2013/01/09/logging-cluster-aware-updating-hotfix-plug-in-installations-to-a-file-share/ for more information on this.

Just like we found that the DRAC upgrade was not succeeding on two nodes.

One it was due to the DUP not being able to access the Virtual USB Device

Software application name: iDRAC6
   Package version: 1.95
   Installed version: 1.92

Executing update…

Device does not impact TPM measurements.

Device: iDRAC6, Application: iDRAC6
  Failed to access Virtual USB Device

==================> Update Result <==================

Update was not applied

================================================

Exit code = 1 (Failure)

and the other was because there was some other lingering DRAC process.

 iDRAC is currently unable to process this request because of another task.
  Please attempt one or more of the following steps to cancel the pending iDRAC task:
  1) Wait 30 minutes and retry your request.
  2) Reboot the system; Press F10; select ‘Exit and Reboot’ from Unified Server Configurator, and retry your request.
  3) Reboot the system; Press Ctrl-E; select ‘System Services’. Then change ‘Cancel System Services’ to YES, which will close the pending task;
      Then press Enter at the warning message. Press ESC twice and select ‘Save Changes and Exit’ and retry your request.

==================> Update Result<==================

Update was not applied

================================================
Exit code = 1 (Failure)

They give some nice suggestions but the racreset is another nice one to have I your toolkit. It’s fast and effective.

Run racadmin racreset soft

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Wait for a couple of minutes and then run the DUP or the items in SUU that failed. With some luck this will succeed now.

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A reality Check On Disaster Recovery & Business Continuity


Introduction

Another blog post in “The Dilbert Life Series®” for those who are not taking everything personal. Every time business types start talking about business continuity, for some reason, call it experience or cynicism, my bull shit & assumption sensors go into high alert mode. They tend to spend a certain (sometimes considerable) amount of money on connectivity, storage, CPUs at a remote site, 2000 pages of documentation and think that covers just about anything they’ll need. They’ll then ask you when the automatic or 5 minute failover to the secondary site will be up and running. That’s when the time has come to subdue all those inflated expectations and reduce the expectation gap between business and IT as much as possible. It should never have come to that in the first place. But in this matter business people & analysts alike, often read (or are fed) some marchitecture docs with a bunch of sales brochures which make it al sound very easy and quickly accomplished. They sometimes think that the good old IT department is saying “no” again just because they are negative people who aren’t team players and lack the necessary “can do attitude” in world where their technology castle is falling down. Well, sorry to bust the bubble, but that’s not it. The world isn’t quite that black and white. You see the techies have to make it work and they’re the ones who have to deal with the real. Combine the above with a weak and rather incompetent IT manager bending over to the business (i.e. promising them heaven on earth) to stay in there good grace and it becomes a certainty they’re going to get a rude awakening. Not that the realities are all that bad. Far from it, but the expectations can be so high and unrealistic that disappointment is unavoidable.

The typical flow of things

The business is under pressure from peers, top management, government & regulators to pay attention to disaster recovery. This, inevitably leads to an interest in business continuity. Why, well we’re in a 24/7 economy and your consumer right to buy a new coffee table on line at 03:00 AM on a Sunday night is worth some effort.  So if we can do it for furniture we should certainly have it for more critical services. The business will hear about possible (technology) solutions and would like to see them implemented. Why wouldn’t they? It all sounds effective and logical. So why aren’t we all running of and doing it? Is it because IT is a bunch of lazy geeks playing FPS games online rather than working for their mythically high salaries? How hard can it be? It’s all over the press that IT is a commodity, easy, fast, dynamic and consumer driven so “we” the consumers want our business continuity now! But hey it costs money, time, a considerable and sustained effort and we have to deal with the less than optimal legacy applications (90% of what you’re running right now).

Realities & 24/7 standby personnel

The acronyms & buzz words the business comes up with after attending some tech briefing by Vendors Y & Z (those are a bit like infomercials but without the limited value those might have Sarcastic smile) can be quite entertaining. You could say these people at least pay attention to the consumerized business types. Well actually they don’t, but they do smell money and lots of it. Technically they are not lying. In a perfect world things might work like that … sort of, some times and maybe even when you need it. But it will really work well and reliable. Sure that’s not the vendors fault. He can’t help  that the cool “jump of a cliff” boots he sold you got you killed. Yes they are designed to jump of a cliff but anything above 1 meter without other precautions and technologies might cause bodily harm or even death. But gravity and its effects in combination with the complexity of your businesses are beyond the scope of their product solutions and are entirely your responsibility. Will you be able to cover all those aspects?

Also don’t forget the people factor. Do you have the right people & skill sets at your disposal 24/7 for that time when disaster strikes? Remember that could be on a hot summer night in a weekend when they are enjoying a few glasses of wine at a BBQ party and not at 10:15 AM on a Tuesday morning.

So what terminology flies around?

They hear about asynchronous or even synchronous replication of storage of applications. Sure it can work within a data center, depending on how well it is designed and setup. It can even work between data centers, especially for applications like Exchange 2010. But let’s face it, the technical limitations and the lack of support for this in many of the legacy applications will hinder this considerably.

They hear of things like stretched clusters and synchronous storage replication. Sure they’ll sell you all kinds of licensed features to make this works at the storage level with a lot of small print. Sometimes even at the cost of losing functionality that makes the storage interesting in the first place. At the network level anything below layer 3 probably suffers from too much optimism. Sure stretched subnets seem nice but … how reliable are these solutions in real live?

Consider the latency and less reliable connectivity.You can and will lose the link once in a while. With active-active or active-passive data centers that depend on each other both become single points of failure. And then there are all the scenarios where only one part of the entire technology stack that makes everything work fails. What if the application clustering survives but not the network, the storage or the database? You’re toast any way. Even worse, what if you get into a split brain scenario and have two sides writing data. Recover from that one my friend, there’s no merge process for that, only data recovery. What about live migration or live motion (state, storage, shared nothing) across data centers to avoid an impending disaster? That’s a pipe dream at the moment people. How long can you afford for this to take even if your link is 99.999% reliable? Chances are that in a crisis things need to happen vast to avoid disaster and guess what even in the same data center, during normal routine operations, we’re leveraging <1ms latency 10Gbps pipes for this. Are we going to get solutions that are affordable and robust? Yes, and I think the hypervisor vendors will help push the entire industry forward when I see what is happening in that space but we’re not in Walhalla yet.

Our client server application has high availability capabilities

There are those “robust and highly available application architectures” (ahum) that only hold true if nothing ever goes wrong or happens to the rest of the universe. “Disasters” such as the server hosting the license dongle that is rebooted for patching. Or, heaven forbid, your TCP/IP connection dropped some packages due to high volume traffic. No we can’t do QoS on the individual application level and even if we could it wouldn’t help. If your line of business software can’t handle a WAN link without serious performance impact or errors due to a dropped packet, it was probably written and tested on  <1ms latency networks against a database with only one active connection. It wasn’t designed, it was merely written. It’s not because software runs on an OS that can be made highly available and uses a database that can be clustered that this application has any high availability, let alone business continuity capabilities. Why would that application be happy switching over to another link. A link that is possibly further away and running on less resources and quite possibly against less capable storage? For your apps to works acceptably in such scenarios you would already have to redesign them.

You must also realize that a lot of acquired and home written software has IP addresses in configuration files instead of DNS names. Some even have IP addresses in code.  Some abuse local host files to deal with hard coded DNS names … There are tons of very bad practices out there running in production. And you want business continuity for that? Not just disaster recovery  to be clear but business continuity, preferably without dropping one beat. Done any real software and infrastructure engineering in your life time have you? Keeping a business running often looks like a a MacGyver series. Lots creativity, ingenuity, super glue, wire, duct tape and Swiss army knife or multi tool. This is still true today, it doesn’t sound cool to admit to it, but it needs to be said.

We can make this work with the right methodologies and strict processes

Next time you think that, go to the top floor and jump of, adhering to the flight methodologies and strict processes that rule aerodynamics. After the loud thud due to you hitting the deck, you’ll be nothing more than a pool of human waste. You cannot fly. On top of unrealistic scenarios things change so fast that documentation and procedures are very often out of date as soon as they are written.

Next time some “consultants” drop in selling you products & processes with fancy acronyms proclaiming rigorous adherence to these will safe the day consider the following. They make a bold assumption given the fact they don’t know even 10% of the apps and processes in your company. Even bolder because they ignore the fact that what they discover in interviews often barely scratches the surface. People can only tell you what they actually know or dare tell you. On top of that any discovery they do with tools is rather incomplete. If the job consist of merely pushing processes and methodologies around without reality checks you could be in for a big surprise. You need the holistic approach here, otherwise it’s make believe. It’s a bit like paratrooper training for night drops over enemy strong holds, to attack those and bring ‘m down. Only the training is done in a heated class room during meetings and on a computer. They do not ever put on all their gear, let alone jump out of an aircraft in the dead of night, regroup, hump all that gear to the rally points and engage the enemy in a training exercise. Well people, you’ll never be able to pull of business continuity in real life either if you don’t design and test properly and keep doing that. It’s fantasy land. Even in the best of circumstances no plan survives it first contact with the enemy and basically you would be doing the equivalent of a trooper firing his rifle for the very first time at night during a real engagement. That’s assuming you didn’t break your neck during the drop, got lost and managed to load the darn thing in the first place.

You’re a pain in the proverbial ass to work with

Am I being to negative? No, I’m being realistic. I know reality is a very unwelcome guest in fantasy land as it tends to disturb the feel good factor. Those pesky details are not just silly technological “manual labor” issues people. They’ll kill your shiny plans, waste tremendous amounts of money and time.

We can have mission critical applications protected and provide both disaster recovery and business continuity. For that the entire solution stack need to be designed for this. While possible, this makes things expensive and often only a dream for custom written and a lot of the shelf software. If you need business continuity, the applications need to be designed and written for it. If not, all the money and creativity in the world cannot guarantee you anything. In fact they are even at best ugly and very expensive hacks to cheap and not highly available software that poses as “mission critical”.

Conclusion

Seriously people, business continuity can be a very costly and complex subject. You’ll need to think this through. When making assumptions realize that you cannot go forward without confirming them. We operate by the mantra “assumptions are the mother of al fuckups” which is nothing more than the age old “Trust but verify” in action. There are many things you can do for disaster recovery and business continuity. Do them with insight, know what you are getting into and maybe forget about doing it without one second of interruption for your entire business.

Let’s say disaster strikes and the primary data center is destroyed. If you can restart and get running again with only a limited amount of work and productivity lost, you’re doing very well. Being down for only a couple of hours or days or even a week, will make you one of the top performers. Really! Try to get there first before thinking about continuous availability via disaster avoidance and automatic autonomous failovers.

One approach to achieve this is what I call “Pandora’s Box”. If a company wants to have business continuity for its entire stack of operations you’ll have to leave that box closed and replicate it entirely to another site. When you’re hit with a major long lasting disaster you eat the down time and loss of a certain delta, fire up the entire box in another location. That way you can avoid trying to micro manage it’s content. You’ll fail at that anyway. For short term disasters you have to eat the downtime. Deciding when to fail over is a hard decision. Also don’t forget about the process in reverse order. That’s another part of the ball game.

It’s sad to see that more money is spend consulting & advisers daydreaming than on realistic planning and mitigation. If you want to know why this is allowed to happen there’s always my series on The do’s and don’ts when engaging consultants Part I and Part II. FYI, the last guru I saw brought into a shop was “convinced” he could open Pandora’s Box and remain in control. He has left the building by now and it wasn’t a pretty sight, but that’s another story.

Hyper-V Cluster Node Pause & Drain fails – Live Migrations fail with “The requested operation cannot be completed because a resource has locked status”


One night I was doing some maintenance on a Hyper-V cluster and I wanted to Pause and drain one of the nodes that was up next for some tender loving care. But I was greeted by some messages:

image

[Window Title]
Resource Status

[Main Instruction]
The requested operation cannot be completed because a resource has locked status.

[Content]
The requested operation cannot be completed because a resource has locked status.

[OK]

Strange, the cluster is up and running, none of the other nodes had issues and operational wise all VMs are happy as can be. So what’s up? Not to much in the error logs except for this one related to a backup. Aha …We fire up disk part and see some extra LUNs mounted + using “vssadmin list writers“ we find:

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Writer name: ‘Microsoft Hyper-V VSS Writer’
…Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
…Writer Instance Id: {2fa6f9ba-b613-4740-9bf3-e01eb4320a01}
…State: [5] Waiting for completion
…Last error: Unexpected error

Bingo! Hello old “friend”, I know you! The Microsoft Hyper-V VSS Writer goes into an error state during the making of hardware snapshots of the LUNs due to almost or completely full partitions inside the virtual machines. Take a look at this blog post on what causes this and how to fix fit. As a result we can’t do live migrations anymore or Pause/Drain the node on which the hardware snapshots are being taken.

And yes, after fixing the disk space issue on the VM (a SDT who’s pumped the VM disks 99.999% full) the Hyper-V VSS writer get’s out of the error state and the hardware provider can do it’s thing. After the snapshots had completed everything was fine and I could continue with my maintenance.

Remote File Browsing Issue In Windows Server 2012 Hyper-V Leaves Results Pane Empty Workaround


In Windows Server 2012 the Remote File Browsing functionality for Hyper-V acts ups on some nodes indicating a problem.

You can read what “Remote File Browsing” is on TechNet here. You use it to browse the file system on a remote Hyper-V server when creating a  new VM there for example.

Remote File Browsing is a shell namespace extension implemented by Hyper-V, it provides a way to browse the folders/files on remove Hyper-V server without requiring server to open extra shell over the network.

The path "::{0907616E-F5E6-48D8-9D61-A91C3D28106D}\HYPER-V-TEST" is to tell shell (explorer or common file dialog) that it is hosting/pointing to the RemoteFileBrowsing shell namespace extension on the HYPER-V-TEST. The guid is Hyper-V remotefilebrowsing shell namespace extension GUID. However, due to the limitation on common file browser, it is not able to translated into "Hyper-V Remote File Browsing".

Now in Windows Server 2012 we sometimes see the following when we use it:

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It seems to work but the result pane remains empty. The cluster is healthy, the nodes are healthy, all nodes are identically configured. Some nodes have it, other don’t. We also can’t find any errors logged anywhere.

If you try to work around it using the UNC path that will fail due to security issues later so don’t even go there Winking smile

Basically we were a bit baffled (we could not reproduce it in the lab either) until we saw some posts on then forums, indicating we’re not the only one seeing this.

http://social.technet.microsoft.com/Forums/en-US/winserverhyperv/thread/608d0c3b-0a7b-4ad9-9843-5e5051dcd526

http://social.technet.microsoft.com/Forums/en-US/winserverhyperv/thread/7a34f5e1-76bc-493a-8a7a-e9f420bf6a79#d7dd4db7-d7bd-419d-aa72-b12e43cd7a5d

If you know your cluster is perfectly healthy forget all the security settings stuff and go straight to testing this “fix” or rather workaround: Toggle Audit Object Access on and off.

In our case I can confirm that these nodes had been under a group policy that audited registry entries during a period that we were trouble shooting network card settings change behavior. We had removed that policy by first reverting the settings to not configured and after some days by removing the GPO. But that didn’t work. Even with no audit policy configured we had to go to all nodes showing this behavior, opening the local Group Policy, toggling our Audit Object Access on for success,applying this and reverting this to No auditing again.

So fire up an MMC, add a snap-in

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Select Group Policy Object

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Accept the defaults

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When don navigate to Computer Configuration -> Windows Settings -> Security Settings -> Local Policy -> Audit Policy -> Audit Object Access

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Now try to use Remote Browser again (close & reopen all wizard windows and start over a new) to see the results:

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Success! All is well again.

Notes:

  • We only see this on systems remotely connecting to Windows Server 2012 Hyper-V nodes that are running Windows Server 2012 or Windows 8 themselves not on Windows 2008 R2 or Windows 7 with the RSAT for W2K12 installed.
  • This is not related to Windows core alone due to missing GUI components or something.

Trouble Shooting Windows Server 2012 host based CommVault Backups with DELL Compellent hardware VSS provider of Hyper-V guests: ‘Microsoft Hyper-V VSS Writer’ State: [5] Waiting for completion


We have been running CommVault Simpana 9.0 R2 SP7 in combination with the DELL Compellent Hardware VSS provider to do host based backups of the virtual machines on our Windows Server 2012 Hyper-V clusters host with great success and speed.

We’ve run into two issues so far. One, I blogged about in DELL Compellent Hardware VSS Provider & Commvault on Windows Server 2012 Hyper-V nodes – Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface. hr = 0×80070005, Access is denied was an due to some missing permissions for the domain account we configured the Compellent Replay manager Service to run with. The solution for that issue can be found in that same blog post.

The other one was that sometimes during the backup of a Hyper-V host we got an error from CommVault that put the job in a “pending” status, kept trying and failing. The error is:

Error Code: [91:9], Description: Volume Shadow Copy Service (VSS) error. VSS service or writers may be in a bad state. Please check vsbkp.log and Windows Event Viewer for VSS related messages. Or run vssadmin list writers from command prompt to check state of the VSS writers.

clip_image001

When we look at the Compellent controller we see the following things happen:

  • The snapshots get made
  • They are mounted briefly and then dismounted.
  • They are deleted

The result at the CommVault end is that the job goes into a pending state with the above error. When we look at the state of the Microsoft Hyper-V VSS Writer by running “vssadmin list writer” …

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… from an elevated command prompt we see:

Writer name: ‘Microsoft Hyper-V VSS Writer’
…Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
…Writer Instance Id: {2fa6f9ba-b613-4740-9bf3-e01eb4320a01}
…State: [5] Waiting for completion
…Last error: Retryable error

Note at this stage:

  1. Resuming the job doesn’t help (it actually keep trying by itself but no joy).
  2. Killing the job and restarting brings no joy. On top of that our friendly error “Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface. hr = 0×80070005, Access is denied.“ is back, but this time related to the error state of the ‘Microsoft Hyper-V VSS Writer’. The error now has changed a little and has become:

clip_image002

 

 

Writer name: ‘Microsoft Hyper-V VSS Writer’
…Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
…Writer Instance Id: {2fa6f9ba-b613-4740-9bf3-e01eb4320a01}
…State: [5] Waiting for completion
…Last error: Unexpected error

To get rid of this one we can restart the host or, less drastic, restart the Hyper-V Virtual Machine management Service (VMMS.exe) which will do the trick as well.  Before you do this , drain the node when you pause it, then resume it with the option failing back the roles. Windows 2012 makes it a breeze to do this without service interruption Smile

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The Cause: Almost or completely full partitions inside the virtual machines

Looking for solutions when CommVault is involved can be tedious as their consultancy driven sales model isn’t focused on making information widely available. Trouble shooting VSS issues can also be considered a form of black art at times. Since this is Windows 2012 RTM an the date is September 20th 2012 as the moment of writing, there are not yet any hotfixes related to host level backups of Virtual machines and such. CommVault Simpana 9.0 R2 SP7 is also fully patched.

This,combined with the fact that we did not see anything like this during testing (and we did a fair amount) makes us look at the guests. That’s the big difference on a large production cluster. All those unique guests with their own history. We also know from the past years with VSS snapshots in Windows 2008(R2) that these tend to fail due to issues in the guests. Take a peak at Troubleshoot VSS issues that occur with Windows Server Backup (WBADMIN) in Windows Server 2008 and Windows Server 2008 R2 just for starters  As an example we already had seen one guest (dev/test server) that had 5 user logged in doing all kinds of reconfigurations and installs go into save mode during a backup, so it could be due to something rotten in certain guests. There is very much to consider when doing these kinds of backups.

By doing some comparing of successful & failed backups it really looks as if it was related to certain virtual machines. A lot of issues are caused by the VSS service, not running or not being able to do snapshots because of lack of space so perhaps this was the case here as well?

We poked around a bit. First let’s see what we can find in the Hyper-V specific logs like the Microsoft-Windows-Hyper-V-VMMS-Admin event log. Ah lot’s of errors relating to a number of guests!

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Log Name:      Microsoft-Windows-Hyper-V-VMMS-Admin
Source:        Microsoft-Windows-Hyper-V-VMMS
Date:          19/09/2012 22:14:37
Event ID:      10102
Task Category: None
Level:         Error
Keywords:     
User:          SYSTEM
Computer:      undisclosed server
Description:
Failed to create the volume shadow copy inside of virtual machine ‘undisclosedserver’. (Virtual machine ID 84521EG0G-8B7A-54ED-2F24-392A1761ED11)

Well people, that is called a clue Winking smile. So we did some Live Migration to isolate suspect VMs to a single node, run backups, see them fail, do the the same with a new and clean VM an it all works. and indeed … looking at the guest involved when the CommVault backup fails we that the VSS service is running and healthy but we do see all kind of badness related to disk space:

  • Large SQL Server backup files put aside on the system partition or or other disks
  • Application & service pack installers left behind,
  • Log and tempdb volumes running out of space.
  • Application Logs running out of control

That later one left 0MB of disk space on the system (Test Controller TFS shitting itself), but we managed to clear just enough to get to just over 1GB of free space which was enough to make the backup succeed.

clip_image001[8]

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Servers, virtual or physical ones, should to be locked down to prevent such abuse. I know, I know. Did I already tell you I do not reside in a perfect world? We cannot protect against dev and test server admins who act without much care on their servers. We’ll just keep hammering at it to raise their awareness I guess. For end users and production servers we monitor those well enough to proactively avoid issues. With dev & test servers we don’t do so, or the response team would have a day’s work reacting to all alerts that daily dev & test usage on those servers generate.

The fix

  • Clear at least 1GB or a bit more inside each partition in the guest running on the host that has a failing backup. I prefer to have at least a couple of GB free  (10% to 15% => give yourself some head room people).
  • Then you can resume the backup job manually or let CommVault do that for you if it’s still in a pending state.
  • If you’ve killed the job make sure you restore the
  • Microsoft Hyper-V VSS Writer  to a healthy state as described above. Thanks to Live Migration this can be achieved without any down time.

Conclusion

There is experimenting, testing, production testing, production and finally real life environments where not all is done as it should be. Yes, really the world isn’t perfect. Managers sometimes think it’s click, click, Next, click and voila we’ve got a complex multisite system running. Well it isn’t like that and you need some time and skills to make it all work. Yes even in todays “cheap, fast, easy to run your business form your smartphone”  ecosystem of the private, hybrid and public cloud, where all is bliss and world peace reigns.

The DELL Compellent Hardware VSS provider & replay manager service handle all this without missing a beat, which is very comforting. As previous experiences with hardware VSS provides of other vendors make us think that these would probably have blown up by now.