Author Archives: workinghardinit

10Gbps Cheap & Without Risk In Even The Smallest Environments

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Over the last 18 months cheaper, commodity, small port count, but high quality 10Gbps switches have become available. NetGear is a prime example. This means 10Gbps networking is within reach for even the smallest deployments.

Size is an often used measure for technological needs like storage, networking and compute but in many cases it’s way too blunt of a tool. A lot of smaller environments in specialized niches need more capable storage  and networking capacities than their size would lead you to believe. The “Enterprise level” cost associated with the earlier SPF+ based swithes was an obstacle especially since the minimum port count lies around 24 ports, so with switch redundancy this already means 2 *24 ports.  Then there’s the cost of vendor branded SPF+ modules. But that could be offset with Copper Twinax Direct Attach cabling (which have their sweet spots for use) or finding functional cheaper non branded SFP+ modules. But all that isn’t an issue anymore. Today 10GBase-T card & switches are readily available and ready for prime time. The issues with power consumption and heat have been dealt with.

While vendors like DELL have done some amazing work to bring affordable 10Gbps switches to the market it remained a obstacle for many small environments. Now with the cheaper copper based, low port count switches it’s become a lot easier to introduce 10Gbps while taking away the biggest operational pains.

  • You can start with a lower number of 10Gbps ports (8-12) instead of  a minimum of 24.
  • No need for expensive vendor branded SPF+ modules.
  • Copper cabling (CAT6A) is relatively cheap for use in a rack or between two racks and for this kind of environment using patch lead cables isn’t an issue
  • Power consumption and heat challenges of copper 10Gbps has been addressed.

8port10Gbps

So even for the smallest setups where people would love to get 10Gbps for live migrations, hypervisor host backups and/or the virtual network it can be done now. If you introduce these for just CSV, live migration, storage or backup networks you can even avoid having to integrate them into the data network. This makes it easier, non disruptive & the isolation helps puts minds at easy about potential impacts of extra traffic and misconfigurations. Still you take away the heavy loads that might be disrupting your 1Gbps network, making things well again without needing further investments.

So go ahead, take the step and enjoy the benefits that 10Gbps bring to your (virtual) environment. Even medium sized shops can use this as a show case while they prepare for a 10Gbps upgrade for the server room or data center in the years to come.

NTFS Permissions On A File Server From Hell Saved By SetACL.exe & SetACL Studio

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Most IT people don’t have a warm and fuzzy feeling when NTFS permissions & “ACLing” are being discussed. While you can do great & very functional things with it, in reality when dealing with file servers over time “stuff” happens. Some of it technical, most of it is what I’ll call “real life”. When it comes to file servers, real life, especially in a business environment, has very little respect, let alone consideration for NFTS/ACL best practices. So we all end up dealing with the fall out of this phenomena. If you haven’t I could state you’re not a real sys admin but in reality I’m just envious of your avoidance skills Smile.

You don’t want to fight NTFS/ACLs, but if it can’t be avoided you need the best possible knowledge about how it works and the best possible tools to get the job done (in that order).

If you have not heard of SetACL or DelProf2, you might also not have heard of uberAgent for Splunk, let alone of their creator, community rock star Helge Klein. If you new to the business I’ll forgive you but if you been around for a while you have to get to know these tools. His admin tools, both the free or the paying ones, are rock solid and come in extremely handy in day to day work. When the shit hits the fans they are priceless.

Helge is an extremely knowledgeable, experienced, talented and creative IT Professional and developer. I’ve met him a couple of times (E2EVC, where he’s an appreciated speaker) and all I can say is that on top of all that, he’s a great guy, with heart for the community.

Having the free SetACL.exe available for scripting of NTFS permissions is a luxury I cannot do without anymore. On top of that for a very low price you can buy SetACL Studio. This must be the most efficient GUI tool for managing NFTS permissions / ACLs I have ever come across.

Not long ago I was faced with a MBR to GPT LUN migration on a very large file server. It’s the proverbial file server from hell. We’ve all been there too many times and even after 15 years plus we still cannot get people to listen and follow some best practices and above all the KISS principle. So you end up having to deal with the fall out of every political, organizational, process and technical mistake you can imagine when it comes to ACLs & NTFS permissions. So what did I reach for? SetACL.exe and SetACL Studio, these are my go to tools for this.

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Check out the web page to read up on what this tool can do for you. It very easy to use, intuitive and fast. It can do ACL on file systems, registry, services, printers and even WMI. It helps you deal with granting ownership and rights without messing up the existing NTFS permissions in an easy way. It works on both local and remote systems. Last but not least it has an undo function, how cool is that?!  Yup and admin tool that let you change your mind. Quite unique.

As an MVP I can get a license for free form Helge Klein but I recommend any IT Pro or consultant to buy this tool as it makes a wonderful addition to anyone’s toolkit, saving countless of hours, perhaps even days. It pays itself back within the 15 minutes you use it.

Other useful tools in your toolkit are http://www.editpadlite.com/ as it can handle the large (550-800 MB) log files RoboCopy can produce and some PowerShell scripting skills to parse these files.

Windows 2012 R2 Data Deduplication Leverages Shadow Copies: “LastOptimizationResultMessage : A volume shadow copy could not be created or was unexpectedly deleted”.

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When you’re investigation and planning large repositories for data (backups, archive, file servers, ISO/VHD stores, …) and you’d like to leverage Windows Data Deduplication you have too keep in mind that the maximum supported size for an NTFS volume is 64TB. They can be a lot bigger but that’s the maximum supported. Why, well they guarantee everything will perform & scale up to that size and all NTFS functionality will be available. Functionality on like volume shadow copies or snapshots. NFTS volumes can not be lager than 64TB or you cannot create a snapshot. And guess what data deduplication seems to depend on?

Here’s the output of Get-DedupeStatus for a > 150TB volume:

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Note “LastOptimizationResultMessage      : A volume shadow copy could not be created or was unexpectedly deleted”.

Looking in the Deduplication even log we find more evidence of this.

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Data Deduplication was unable to create or access the shadow copy for volumes mounted at "T:" ("0x80042306"). Possible causes include an improper Shadow Copy configuration, insufficient disk space, or extreme memory, I/O or CPU load of the system. To find out more information about the root cause for this error please consult the Application/System event log for other Deduplication service, VSS or VOLSNAP errors related with these volumes. Also, you might want to make sure that you can create shadow copies on these volumes by using the VSSADMIN command like this: VSSADMIN CREATE SHADOW /For=C:

Operation:

   Creating shadow copy set.

   Running the deduplication job.

Context:

   Volume name: T: (\?Volume{4930c926-a1bf-4253-b5c7-4beac6f689e3})

Now there are multiple possible issues that might cause this but if you’ve got a serious amount of data to backup, please check the size of your LUN, especially if it’s larger then 64TB or flirting with that size. It’s temping I know, especially when you only focus on dedup efficiencies. But, you’ll never get any dedupe results on a > 64TB volume. Now you don’t get any warning for this when you configure deduplication. So if you don’t know this you can easily run into this issue. So next to making sure you have enough free space, CPU cycles and memory, keep the partitions you want to dedupe a reasonable size. I’m sticking to +/- 50TB max.

I have blogged before on the maximum supported LUN size and the fact that VSS can’t handle anything bigger that 64TB here Windows Server 2012 64TB Volumes And The New Check Disk Approach. So while you can create volumes of many hundreds of TB you’ll need a hardware provider that supports bigger LUNs if you need snapshots and the software needing these snapshots must be able to leverage that hardware VSS provider. For backups and data protection this is a common scenario. In case you ask, I’ve done a quick crazy test where I tried to leverage a hardware VSS provider in combination with Windows Server data deduplication. A LUN of 50TB worked just fine but I saw no usage of any hardware VSS provider here. Even if you have a hardware VSS provider, it’s not being used for data deduplication (not that I could establish with a quick test anyway) and to the best of my knowledge I don’t think it’s possible, as these have not exactly been written with this use case in mind. Comments on this are welcome, as I had no more time do dig in deeper.

Virtualizing Intensive Workloads on Hyper-V, Can It Be Done?

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Can it be done?

All I can say is that, yes, absolutely, you can virtualize resource intensive workloads. Done right you’ll gain all benefits associated with virtualization and you won’t lose your performance & scalability.

Now I have to stress done right. There are a couple of major causes of problems with virtualization. So let’s look at those and see how a few well placed torpedoes can sink your project fast & effective.

Common Sense

One of them is the lack of common sense. If you currently have 10 SQL Servers with 12 15K RPM SAS Disks in RAID 1 and RAID 10 for the OS, TempDB, Logs & Data files, 64 GB of Memory, dual Quad Core sockets and teamed 1Gbps for resilience and throughput and you want to virtualize them you should expect to deliver the same resources to the virtualized servers. It’s technology people. Hoping that a hypervisor will magically create resources out of thin air is setting yourself up for failure. You cannot imagine how often people use cheap controllers, less disk or slower disks, less bandwidth or CPU cycles and then dump their workload on it. Dynamic memory, NUMA awareness, Storage QoS, etc. cannot rescue a undersized, ill conceived solution. I realize you have read that most physical servers are sitting there idle and let their resources go to waste. If you don’t measure this you can get bitten. You can get ripped to pieces when you’re dealing with virtualizing intensive workloads on Hyper-V based on assumptions.

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Consider the entire stack

The second torpedo is not understanding the technology stack. The integration part of things or the holistic approach in management consulting speak. The times one could think as a storage admin, network admin, server admin, virtualization admin, SQL DBA, Exchange Engineer is long gone. Really, long gone. You need to think about the entire stack. Know your bottle necks, SPOF, weaknesses, capabilities and how these interact. If you’re still on premise for 100% that means you have to be a datacenter admin, not forgetting you might have multiple of those. And you’d better communicate a bit through DevOps to make sure the developers know that all those resources are not magically super redundant, are not continuously available without any limitation and that these do not have infinite scalability.

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Drivers, firmware & bugs can sink your project

Hardware, VAR & ISV support is also a frequent cause of problems. They’ll al tell you that everything is supported. You can learn very fast and very painfully that this is too often not the case or serious bugs are wreaking havoc on your beautiful design. So I live by one of my mantras: “Trust but verify”. However sad it may be, you cannot in good faith trust OEM, VAR and ISVs. I’m not saying they are willfully doing this, but their experience, knowledge isn’t perfect & complete either. You have to do your due diligence. There are too many large scale examples of this right now with Emulex NIC issues around DVMQ. This is a prime example of how you slow acknowledgement of a real issue can ruin your virtualization project for intensive workloads and has been doing so for 9 months and might very well take a year to resolve. Due diligence could have saved you here. A VAR should protect its customers from that, but in reality they often find out when it’s too late. Another example is bugs in storage vendors implementation of ODX causing corruption or extremely slow support for a new version of Windows effectively blocking the use of it in production when you need it for the performance & scalability. I have long learned that losing customers and as such revenue is the only real language vendors understand. So do not be afraid to make hard decisions when you need to.

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Knowledge & Due Diligence

Know your hypervisor and core technologies well. Don’t think it’s the same a hardware based deployments, don’t think all options and features work everywhere for everything, don’t think all hypervisor work the same. They do not. Know about Exchange and the rules/limits around virtualization. The same goes for SQL Server and any resource intensive workload you virtualize. Don’t think that the same rules apply to all workloads. There is no substitute for knowledge, experience and hands on testing, the verification part of trust but verify, remember? It goes for you as well!

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It can be done

Yes, we can Winking smile! If you want to see some high level examples to simulate your appetite just browse my blog. Here are some pointers to get you started.

Unmap

 

 

Live migration at the speed of light

Remember , don’t just say “Damn those torpedoes, full speed ahead” but figure out why, where, when and how you’ll get the job done.