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Category Archives: Hardware

Disaster Recovery

I have recently been sucked into all that is Disaster Recovery or Business Continuity Planning. Previously I have been a bit dodgy of the topic. I haven’t really enjoyed the subject because it always seems to distract from my focus on backups and local recovery. I liked to focus on the more likely failure scenarios and make sure those are covered before we get distracted. I’m not really sure if that was a good plan or not.

We would have to loose almost our entire datacenter to trigger our disaster recovery plan. A fire in the datacenter, tornado or maybe loosing our key storage array might trigger DR. Dropping a table in a business application isn’t something you want to trigger a DR plan. Developing a highly available, resilient system is a separate task from developing a DR plan for that system. It was very challenging to convince people to complete a discussion of the local recovery problems without falling into the endless pit of DR.

There seems to be two different business reasons for DR. 1. Complete a test of the plan so we can pass an audit once a year and 2. Create a plan so we can actually recover if there were a disaster. The first one comes with a few key caveats, the test must be non-disruptive to business, it cannot change the data we have copied offsite and it cannot disrupt the replication of the data offsite.

In a cool or warm DR site, the hardware is powered on and ready but it is not actively running any applications. If I were to approach this problem from scratch, I would seriously consider a hot active site. I hear metro clusters are becoming more common. Sites that are close enough for synchronous storage replication enable a quick failover with no data loss. A hot site like this would have many benefits including:
1. Better utilization of hardware
2. Easier Disaster Recovery testing
3. Planned failovers for disaster avoidance or core infrastructure maintenance

However, there are downsides…
1. Increased complexity
2. Increased storage latency and cost
3. Increased risk of disaster affecting both sites because they are closer

Testing is vital. In our current configuration, in order to do a test we have to take snapshots at the cold site and bring those online in an isolated network. This test brings online the systems deemed critical to business an nothing more. In an active/active datacenter configuration, the test could be much more thorough where you actually run production systems at the second site.

A most basic understanding of DR covers the simple fact that we now need hardware in a second location. There is much more to DR than a second set of servers. I hope to learn more about the process in the future.

 
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Posted by on February 7, 2015 in Hardware, Storage, Virtual

 

Comparing Server Processors

To pick the best processor for your server, a cursory understanding of how the application works is helpful. In virtulaized environments, that gets interesting because multiple applications run together on the same socket. Generalized compute clusters have their benefits, but some applications have “special needs.” Minimum support requirements could throw a wrench into your choice.

Single Threaded Applications

Multi-threaded code is challenging to write. That is why, even 10 years after multi-core processors became main stream, developers still write single threaded applications that require performance. If you are interested in the code side of this discussion, I wrote a simple post comparing single and multi threading https://nujakcities.wordpress.com/2010/11/16/single-vs-multi-threading/

If you have ever added a core to a VM and watched a process that used to run at 100% CPU on one core, now run at 50% CPU on two cores, you probably have a single threaded application. A multi-threaded process would be able to utilize all cores to 100%. Single threaded applications that cannot be upgraded to utilize multiple threads will benefit from higher clock speeds and not more cores.

Launch Date

This is the first thing I look at after I’ve flushed out any special requirements. I take the processor number from the server quote and find it on the manufacturer’s website. That way I can find out if I am looking at the latest processors. Since Moore’s law is still in play, I can be somewhat comfortable that the newer processor is going to be a lot faster in some way shape or form. If you are not comfortable jumping on the latest technology, you will also save quite a bit of money. Don’t let your hardware vendor talk about new processor features and slip an old one in the quote.

Clock Speed and Core Count

These are the two main factors. They are in the same heading because of the heat balancing act. Faster is hotter, and more cores is also hotter. We unfortunately can’t have the best of both worlds or the box will catch on fire.

If we compare two of the Q’14 high end Intel CPUs, we find the balance was found at 3.4 Ghz/6 cores and 2.8 Ghz/15cores. As a virtualization admin I see an obvious choice here going with 15 physical cores because 99% of my applications would be happier. Even if they are a single threaded applications, the additional .6GHz will be barely noticeable.

Knowing your application can come in handy when designing clusters and buying hardware. Enterprise code can sometimes be a decade old so be cautious of purchasing max cores over high GHz. You may run into more single threaded, latency sensitive application that you want to admit still exist.

If you have a need to run higher core count VMs, a higher number of physical cores per socket is best. I have a general rule of thumb to avoid creating VMs that have more vCPUs than pCores on a single socket. Even if it is a dual or quad socket server, you will see diminishing returns and sometimes problematic ready times if you are spanning a VM across several physical sockets.

Hyperthreading and Turbo

I remember owning a beige PC that had a nice button and red LED display. Press it once and the display would read 33 press it again and it would read 66. Even today, processors have an automatic turbo button however there are some caveats. Turbo won’t work if all of your cores are in high demand. If only a single core is in high demand and the others are idle, then Intel’s “Max Turbo Frequency” value kicks in.

Hyper threading sounds like a great idea but doesn’t actually perform as advertised. I like to refer to these as fake cores. With it on, your OS will see twice the cores. Sometimes they can help but I can guarantee it won’t give you a 2x performance improvement. It really depends, but I have heard ballpark estimates in the range of 25-50% performance improvement by turning on hyper-threading. So I do recommend turning this feature on, but be careful not to mix up physical core count with the hyperthreaded core count.

Cache sizes

About the only thing I understand in this field is cache is good. If some is good, more is probably better. In this area, server CPUs tend to blow Desktop CPUs out of the water. I’ll have to do some more research and testing to figure out if this value should be of great concern which buying processors.

Price

With software like SQL Server licensing by physical core, more than just the hardware costs need to be reviewed. If you are paying by the core or socket for premium software, it makes a lot of sense (and cents) to buy the best processors you can find. If you can increase the consolidation rate, you won’t need so many software licenses.

That is a big IF though. Make sure you are actually getting solid returns on high end processors. Some benchmarks have shown diminishing returns as manufacturers push the limitations. Lay it all on the table, even smaller or abstract costs like reliability, power consumption and productivity before making your decision. Most of all, have fun shopping!

 
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Posted by on February 24, 2014 in Hardware

 

Dell Inspiron 15R i15RM-6366sLV Review

I’ve added a new laptop to the fleet.

dell

side_dell

Here is the basic specs:

15.6″ Screen
Intel Core I5-4200U
6GB Memory
500GB Hard Disk
Windows Home
DVD RW Drive
6-Cell Battery

I ordered directly from Dell and with free shipping the total cost was $589.52.

The Bait (4th Gen i5 processor)

Besides the price, getting some tech that was released in June was attractive. It is a duel core hyper threaded turbo boosting proc which gives Windows 4 available logical processors. The new “Haswell” generation makes several architectures improvements which are detailed here: http://ark.intel.com/products/75459/Intel-Core-i5-4200U-Processor-3M-Cache-up-to-2_60-GHz?wapkw=4200u

A quick search on Tom’s Hardware has a couple people putting the 4th gen performance boost only around 5-7% over the 3rd gen. This processors runs in the range of .75Ghz to 2.5GHz depending on what the demand for CPU cycles is. Dell has it’s own power plan which is on by default. The balancing act of horsepower vs. battery life is key in laptops. I’ve noticed some very small slowdowns which can be easily avoided by turning the power plan to high performance.

dell_perf

high_perf

Hard Drive

I didn’t think I would buy another computer without a solid state drive. But, I have gone an done it again to save a few hundred dollars up front. I do not like what manufacturers are doing with hybrid drives. The technology has advanced but the laptop manufactures are trying to squeeze every last penny out of the old HDD by mixing in a tiny amount of solid state storage. I decided not to pay a premium for the hybrid drive or a super premium for a full SSD out of the box. I can buy a nice 128GB SSD for $100 later when I want to upgrade. I opened a support chat and told them I wanted a fresh Windows install. They made an exception and are sending me a Windows installation DVD so I can use that later when I get the SSD.

The classic HHD performs poorly as expected.

C:\Program Files (x86)\SQLIO>sqlio -kW -t24 -o10 -frandom -b4 -BH -LS
IOs/sec: 674.15
MBs/sec: 2.63
Min_Latency(ms): 3
Avg_Latency(ms): 354
Max_Latency(ms): 679

HDDs are not designed for random activity so that is why the latency is so high. I chose a larger IO size and file and was able to peak out at 95MB/sec in another test. The Windows Experience Index rates this HDD as a 5.9 out of 9.9.

wer

Design

It’s got a nice solid frame and is under 1″ thick. The power adapter is tiny compared to any I have had in the past which was a nice bonus. The keyboard is solid and has a number pad, but it is not back lit. The touchpad works nicely but is lacking the ability scroll. Overall it feels much more sturdy than my HP in the same price range.

TL;DR
To stay in my price range I sacrificed HDD performance and some RAM for the latest processor and durable design.

 
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Posted by on September 22, 2013 in Hardware

 

Hard drive performance in the HP ENVY dv6-7247cl

The Windows Experience Index(WEI) is a tool built into Windows that will test the core components of your computer. I like this tool a lot because it’s easy and takes into account the idea of a bottleneck. Windows 7 had a WEI scale from 1.0-7.9 which didn’t make much sense to me. Windows 8 WEI has a new scale from 1.0-9.9. I’m not sure the thinking here but I hope they eventually update the WEI for Windows 7 to use a 1-10 scale instead of the weird 1-7.9 scale.

My Windows 7 desktop got an outstanding score of 7.1. Even with a solid state drive, the primary hard disk transfer rate was the limiting factor. I was frustrated for years because processors, graphics and memory had made huge performance gains but the old HDD was still slow as molasses. I rejoiced as this issue was address with solid state drives. Even with the roll-out of SSDs, that primary hard disk component is still the bottleneck. Attempts to mask this bottleneck with lots of RAM and more efficient use of storage can only go so far. On my new SSDless HP laptop this bottleneck is noticeable.

5.9... booooo

5.9… booooo

I want to dive a bit deeper into that bottleneck so see how bad it really is. No, we’re not going to be doing this: http://www.youtube.com/watch?v=tDacjrSCeq4 – Shouting at JBODs We’re just going to be runing SQLIO.

It’s difficult to simulate real user activity and get some kind of measurable result that is comparable across systems. I’m going to take an easier route and use a program called SQLIO to let me know how fast my HP ENVY’s HDD really is. WEI thought it was kind of slow (5.9 out of 10) so lets see what SQLIO has to say.

My desktop’s SSD got some excellent marks. These SQLIO parameters test writing small IOs, randomly which is similar to normal user activity.

C:\SQLIO>sqlio -kW -t24 -s20 -o10 -frandom -b4 -BH -LS -F1file1drive1th.txt
IOs/sec: 24349.23
MBs/sec: 95.11

24K+ iops on a test like that is impressive. As a reminder, this hardware got a 7.1 out of 7.9 on WEI.

Now for the feature, the results from my HP ENVY.

C:\SQLIO>sqlio -kW -t24 -s20 -o10 -frandom -b4 -BH -LS -F1file1drive1th.txt
IOs/sec: 1140.55
MBs/sec: 4.45

So for you people who don’t like math, my SSD is ~20X faster than the new HDD in my laptop. My start up time, application load time, context switching(which causes paging) and my virtualization is suffering because of this old fashion technology in my shiny new laptop. After several other tests I was only able to peak at 100MBs/sec with a large sequential style of disk activity that most users just won’t do.

Even thought I have pointed out a very slow component in this laptop I don’t think it should be too concerning. HDDs are still used today because they are more durable and more reliable, not to mention a lot cheaper per GB of storage. The 8GB of RAM does help compensate for this shortcoming.

If you happened to budget $100-$200 more you can still upgrade. Keep an eye on http://www.slickdeals.net. I’ve seen good SSDs near $0.60/GB. I would suggest 120GB or more for a Windows 8 machine. Maybe spend an additional $30 and get an external hard drive enclosure for the old HDD so you can store backups or larger files on it.

The hardware part of the upgrade is easy. First power down the laptop, remove the battery and then press the power button again to deplete any stored power. Be careful when you set the laptop on it’s top because the material is actually plastic and not metal like I had originally thought. With 3 screws you can have the HDD partially removed.

hdd_hp1

Once you get the new drive put in the easy part is over. Now you will have to re-install the OS. HP might be able to send you an operating system install disk but I’m not sure how they are handling that these days. I’m not going to find out because, for now, I’m perfectly happy with the old HDD.

 
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Posted by on December 8, 2012 in Hardware

 

HP ENVY dv6-7247cl 48 hour review

No matter what you say about Black Friday, I still believe. I believe its a great day for America, and it’s a great day for deals.

http://www.samsclub.com/sams/hp-15-6-dv6-laptop-15-6-core-i7-bf/prod7930392.ip?navAction=

My wife and I have never really liked our 17″ Gateway laptop. The size is our main complaint. It only fits in one of our several carrying cases. The power adapter didn’t hold up to the wear and tear that mobile computers are known for. The battery only lasted about 2 hours on it’s best charge. And more recently I needed more memory to run virtual machines.

I had been shopping for a laptop for my Sister so I knew what was available. Without too much thought we saw a Black Friday ad in the Sam’s Club flyer and picked up an HP ENVY dv6. Well, I should thank my wife for waiting in line for 50 minutes to pick this up for me while I was in the woods hunting.

sexy

I was a little hesitant to go with HP. Ever since their tablet flop I haven’t heard much about their hardware. But my other favorite PC brand DELL hasn’t been all that great either. Similar specs for a DELL would have been at least $200 more. So I was quite happy with a $600 laptop that had in it an i7 and 8GB of RAM.

I had many reservations about Windows 8. We’ve had a Windows 8 box at work so we could get used to it but I have avoided it like the plague. I usually dive right into new tech but I’ve had a lot on my plate so this HP is my first real hands on experience with Windows 8.

The smell of new PC really gets my motor running. I fired it up and answered a few question that were normal Windows install questions. I didn’t really care for the lingo while I was waiting. “Please wait while we do some things”… really “things”. I liked the fact that it showed a quick intro video while the install was running. I wish it would have covered some more stuff.

The hardware itself is sexy. I think HP has always been a little more attractive than most PCs. But, just like a cheerleader from 300 level seats, this one is good from far… but far from good. The sides and bottom are plasticy while the top surfaces are a evenly brushed metal. It’s a little larger and heavier than I expected. I think this is an area for improvement.

After the fairly lengthy install process of Windows 8 I logged in and noticed right away the touchpad leaves a little bit to be desired. It is a little jumpy. One tweak that made it better was increasing the mouse speed. It took me forever to find the control panel. Turns out that short video in the beginning and the search button is quite helpful.

The keyboard looks awkward but actually works very well. There are spaces between the keys but that actually helps quite a bit and debris doesn’t get caught in there very easily. The keyboard is not backlit but if you angle the monitor down a bit that is not a problem.

I installed VMWare Player and setup a Win2012/SQL2012 vm. I had to get into the bios (f10) and enable the VT-d support. That allows me to run 64bit vms which my old laptop did not even though it was a 64bit processor.

I like the new file transfer meter, the estimates seem a bit more accurate at first glance. During the install of sql I popped open the resource monitor and noticed 40ms response times on the hard disk. SSD was one feature I wanted but I figured I could upgrade later. I’m not sure what I’ve got for extra bays but I may have to splurge on that sooner rather than later. O well, at least I won’t have to be that prudent with the 700GB c: drive.

My sister mentioned to me she had read that the HP wireless cards are not good and drop connections all the time. I’m happy to report that hasn’t happened once (yet) on two different routers.

The screen in glorious. Out of the box the max resolution is 1366×768. That causes a slight problem because the min resolution on server 2012 is 1024×768 so unless the vm is in full screen mode it requires scrolling.

The battery life meter has been quite accurate. A fresh charge was reporting about 5 hours of life. I’ve switched the power plan over to high performance and I might have to find myself a toggle widget for that.

The AC adapter is poorly positioned for an right handed external mouser. The AC adapter also feels pretty cheap in general, wouldn’t be surprised if I have to replace that within a year. It is fairly small which is convenient for travel.

HP Beats audio leaves a bit to be desired… but I suppose that is my own fault. When I was young I was really into bass. I was the jerk who shook the china off your walls when he drove by. I quickly grew out of that phase but have always maintained a taste for the finer sub woofers in life. There is a tiny little “sub woofer” in the bottom of the laptop that probably helps with marketing. Granted, this is the best sounding laptop I’ve heard. It does create some convenience to maybe streaming a movie while relaxing in bed and not have to hook up speakers or headphones.

The DVD tray is flimsy piece of crap… I’ll probably have to fix that at some point in the next year. I like the convenience of having a DVD drive and noticed some of the slimmer laptops didn’t have one. Given the choice now I might consider going optical drive less. Also, no blue-ray… I don’t own a blue-ray player yet but haven’t really needed one since I can stream movies and shows from my xbox.

The HP bloatware is off the charts.

I uninstalled Norton and Office trial right away. Some of the other things I will have to do some research on later. I uninstalled “simple pass” which kept re-pinning itself to the quick launch bar. Turns out this might be the biometric software and I should have left it be.

Overall this is a great value for a powerful laptop. I have enjoyed it thus far and stay tuned for more posts that include tips, tweaks, complaints and praises for the HP ENVY dv6.

 
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Posted by on November 24, 2012 in Hardware

 

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