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Storage virtualization types, advantages and disadvantages

Virtualization is not a new technology but it has recently become a popular method for making data center management and operations an efficient and effective data center. Storage virtualization is one of the seven types of virtualization and it is extensively being used by IT companies and organizations.


Storage virtualization has two main types that are dependent on the implementation method.

  1. Host-based storage virtualization

In this type of storage virtualization, software such as Logical Volume Manager (LVM) is used on the hosts. LVM is used for mapping of the physical disks to the storage logical pools. A pool of disks can also be created with this software which can then be allocated to servers. SAN, NAS and direct attached storage can be used for the provisioning of the disk.

Abstraction creation of storage devices has been here for a very long time. The configuration of storage systems can be done in any RAID type i.e. 0, 1 and 10, etc.  Once the configuration is done, the logical volume can be created. These volumes are then assigned to servers which view them as disks. The host is shown data on a single disk but in reality, it can be spread over multiple physical disks.

  1. Appliance-based storage virtualization

For those who require disk pools that contain multiple storage arrays, appliance-based storage virtualization is used. In this type, there is a control node, comprising of more than two servers, that controls the allocation of storage from devices to servers. Appliance storage virtualization has a lot of similarities with logical volume manager’s volume group. There is only one stark difference between them and that is their scale.


Given below are the advantages of using storage virtualization:

  1. With this virtualization technology, you can utilize more than one storage array type with your company’s SAN. Migrations can be made with ease and agility because servers cannot differentiate between storage array types. This scale of virtualization comes with high availability, fast speed of migration and minimum possible downtime thanks to its software mirroring feature.
  2. Management of data centers become an extremely easy task with this virtualization type. With storage virtualization, enterprise-level organizations and medium level businesses can benefit greatly as the cost and complexities associated with manageability are greatly reduced. A single console operated by one or two employees instead of an entire team managing the multiple arrays is a blessing.


Like every technology, storage virtualization also has a few disadvantages that are listed below:

  1. When we talk about a single console responsible for management of all your storage then, in theory, this can sound as the most ideal situation but in reality, this single console can become a horror story when software upgradation is required on the storage controlling node. A failover node might hang because of an upgrade fail which in turn can create problems for the apps that utilize provisioned storage.
  2. There is also the issue of scaling capacity in this virtualization. A storage software might not be scalable for allocation of a certain amount of virtual disks but this issue can be catered by increasing the limit via more servers.


Even with its disadvantages that are mentioned above, the advantages of storage virtualization cannot be ignored. Benefits associated with appliance storage virtualization range from increasing capacities, the creation of robust environments and high level of efficiency.

If you are looking for a reliable solution then free virtual appliances is perfect for your company. SA provides its users with high performance and free round the clock support. It also has built-in gateways for connection with public clouds. This allows efficient implementation of a Disaster Recovery plan. This solution is economical and provides the clients with 3-2-1 backup rule. It is scalable and a fully customizable solution with no requirements of any antivirus program, anti-malware or external backup. You can even extend the capacity of Hyperconvergence Appliance with SA.

Time to think about replacing the hard disk in my DS211+

One year ago I bought my Synology DS 211+ with two Western Digital 2TB hard disks and I must say I think about disks replacement. The two 2TB WD hard disks in my NAS are not broken or performing poorly but new hard disks are not bad at all. Currently I have the money for two new hard disks for my DiskStation so I do consider buying new hard disks. But hard disks are still expensive because of the flooding in Thailand which is a country that exports a lot of hard disks.

I think I will wait another six months and see if the prices decreasing. I will still buy two new Western Digital hard disks and replace them with my old drives. The Western Digital green hard disks are still the preferred disks because of the large capacity, OK performance and the low power consumption.

Synology releases the DSM 4.1 Beta Program

Synology releases the DSM 4.1 Beta Program and you can join it now by going to the following URL: I do recommend that you read the text carefully on the page before applying in order to understand what you are applying for.
Notice the following BEFORE you apply.

  1. The DSM 4.1 beta is for evaluation purpose only. It is suggested that you always back up data on your Synology NAS to other locations first. Synology holds no responsibility for any data loss caused by the DSM 4.1 beta.
  2. The DSM 4.1 beta is NOT REVERSIBLE (VERY IMPORTANT); you will not be able to downgrade the DSM on your Synology NAS to a previous version.
  3. The DSM 4.1 beta can only be applied to Synology NAS with DSM 4.0-2198 and onward.
  4. You are encouraged to report bugs and suggestions to the Beta Program manager.

Win a Synology DS212air

If you do a good job in finding bugs you maybe the lucky person that will receive a Synology DS212air as bonus for your work.
If you join the program good luck in finding bugs and help improve the stability of the Synology DSM.

Where to place your NAS at home

March 30th, 2012

When you have bought a NAS it does matter where you place the NAS device in your home because like other electronic devices a NAS should be handled with care. If your NAS is running 24/7 and it has become one of the gadgets in your home that is used all the time you should place the NAS in a safe place. Here are some things to think about, when you are about to find a suitable location for your NAS look for adequate power, network access and cooling. These recommendations are based on my own experiences:

  1. Keep your NAS away from sun light.
  2. Keep your NAS away from children.
  3. Do not place the NAS where you can not hear the beeping sound from your NAS if it starts to beep.
  4. Place your NAS close to other devices such as routers, modems and so on.

My DS211+ is placed in a high bookcase where it is out of reach from children and away from sun light but still visible.

Lost my 4K resolution on my Mac Mini with Mac OS X Yosemite

After the upgrade to Mac OS X Yosemite I can no longer use the 4K resolution on my Mac Mini 2012. The option for the 3440 x 1440 resolution is just no longer available. So my LG 34um95 4K display is currently not a 4K display. It seems that I am not the person in this world that this problem. Other Mac users have the same problem. According to this thread on an Apple forum there is a solution to the problem. Use the old Mac OS X Maverick AppleIntelFramebufferCapri.kext kernel extension with a slightly modification.
My Mac Mini is a small beast with 16 GB RAM, 500 GB SSD and a quad core 2.6 Ghz CPU but the Intel HD4000 chip is just not the best option for 4K displays but it worked under Maverick and I knew that.

I tried to see if could restore the 4K resolution but with no luck. It is just not a good idea to play around with the kernel extension in Apple but I certainly learned a few things about the Mac OS X kernel API, caching and file locations. Several people seems to have fixed the problem.
3 solutions exists for me at the moment:

  1. Revert to Maverick OS X
  2. Use the Maverick AppleIntelFramebufferCapri.kext in order to patch the running Yosemite on my Mac Mini.
  3. Apple will this in the future (not likely)

I am not sure that Apple will ever fix this. I do know that Apple is aware of the problem as it has been reported during the Yosemite Beta testing. This really irritates me a lot. Come on Apple, fix this.

Finally fixed this. After the whole patching circus i found a little trick for display more resolution options. Go to System Preferences in Yosemite -> Displays -> Display tab. Hold down option + left mouse click on Scaled. BOOM! Now the 3440 x 1440 resolution could be selected.

Synology Cloud Station vs Dropbox. What to use?

I have been using Dropbox for some time now and Dropbox is a great way to store data in the cloud, and I do use Dropbox on my iPhone, iPad and Mac. In that way many of my files can be accessed on multiple devices. But I do NOT trust Dropbox when it comes protecting and snooping my data. So most of my data is encrypted BEFORE placed on Dropbox servers but files that contains data with no importance I do not encrypt.
For some time I have planned to create my own cloud via Synology Cloud Station. The whole concept by having my own cloud is total control of my data and that is something that is very important to me. The problem with having my own cloud is the maintenance and the setup which could lead to a bit more work but I do think it is time well spent.

Synology Cloud Station setup

Synology has made a very nice tutorial for setting up the Cloud Station on a Synology NAS device. Just follow the tutorial then you should be good to go. If you want to access the Cloud service from outside your local network you should make a port forward to port 6690 on your router. Remember to enable SSL.
Is is also possible to use Synology QuickConnect. With QuickConnect you just create a unique ID for your device, so you can access your data everywhere. With QuickConnect there is no need to portward to your router because you send your internal and external IP address to a server which stores this data for easy lookup. A nice service but I stick to port forwarding because I know it works.

I think I will go for a private cloud very soon but still have the Dropbox account. Creating a hybrid cloud could also be something to test. Synchronize the private cloud with Dropbox. It could very well work but this setup could be dangerous and should be tested, before actual use.

The Synology DS214+ NAS as a replacement NAS

My good, old but very trustworthy Synology DS211+ NAS is till going strong for the fourth year in row. No hard disks failures, no critical system failures except for the system fan that I had to replace. I am currently looking for a replacement NAS and the Synology DS214+ is the one I am looking for. When I look at some of the hardware specifications in DS214+ I am pretty convinced that is the one I am going to buy.

  • Dual Core CPU
  • 1 GB DDR RAM (Double on memory)
  • Supporting 12 TB storage (Currently I have 2 TB which is not going to last forever)
  • Dual LAN support (I do not need that but nice to have)

Two new WD Red hard disks

Western Digital has made some nice hard disks for NAS devices called WD Red which should be the perfect match for any NAS. So far I have only heard positive things about the WD Red disks. They are fast, stabil and do not use that much energy.

If anyone got any experiences with the Synology DS214+ please respond with a comment. I would like to know if I am on the right track buying this device.

Recently moved from Macports to Homebrew on my Mac

For some time I was using Macport as the easiest way to install and manage common libraries and utilities that are not bundled with Mac OS X. Usually I did not have that many problems with Macports and was actually happy with the usage. But then a colleague of mine showed me Homebrew I was pretty excited and I must say I was blown away how easy it was to use and manage. I really liked the idea that you can place the Homebrew installation anywhere you like. I do not think you have that option with Macports.

One major difference between Homebrew and Macports and the reason why I now prefer homebrew is that, it will not overwrite things that should be installed “natively” in Mac OS X. This means that if there is a native package available, homebrew will notify you instead of overwriting it and causing problems further down the line. This is actually quite nice.
Another thing I really like about Homebrew is the git integration. It is all git and Ruby under the hood. I am a big fan of git.

2013 MacBook Air uses PCIe flash for storage

The Apple MacBook Air 2013 uses PCIe (PCI express) flash in order to store data and the read and write of data is fast, very fast. When I added an OWC 480 GB 6G SSD to my Mac Mini earlier this year, I never thought I would see better read and write operations for a while but I was wrong. My new 13 MacBook Air with PCIe flash is faster than my Mac Mini when it comes to I/O operations. The MacBook Air is capable of reading data with a bandwidth that is higher than 700 MB/s.
I had to read a bit about the PCIe standard in order to find out why the PCIe is so fast.

PCI Express or just PCIe is a high speed bus which is capable of delivering a very high data throughput and that is just what we want. When the MacBook Air uses PCIe it avoids the potential SATA bottleneck and thereby use a more native data transfer.
I did a read/write test with the Disk Speed Test tool and I was very impressed by the performance. The MacBook Air is capable of writing with more than 420 MB/s and reading with more than 710 MB/s with these numbers in mind I had to compare them with my OWC Mercury EXTREME Pro 6G SSD. See the numbers in the table below.

Storage device Read Write
OWC Mercury EXTREME Pro 6G SSD 520 MB/s 435 MB/s
MacBook Air PCIe flash 716 MB/s 429 MB/s

The new 2013 Mac Pro also uses PCIe flash for storage so it will be interesting to see some benchmarks from the beast when it will reach the public later this year.

I you are going to get a new MacBook Air I strongly recommend to upgrade RAM. 4 GB RAM is not enough those days so add the extra 4 GB and reach 8 GB RAM total. You can not upgrade from 4 GB RAM to 8 GB RAM yourself, because the modules are molted to the motherboard so unless you are a technical genius and can do the upgrade yourself buy the extra RAM.

Using Apple Time Machine for multiple computers

It is possible for Apple Time Machine to backup more than one
computer and this feature should be used if possible. If you have more
than one Apple computer that needs to have a backup I would strongly
recommend Apple Time Machine. Apple Time Machine handles multiple
computers perfectly.

I just bought a new MacBook Air and even
though the data on the new MacBook Air is not that different than the
data on my Mac Mini I still want to have the data backed up separately.
The backup for each computer is stored in a separate folder on the
associated Time Machine drive.

Currently my Time Machine backup is located on my Synology NAS211+ so my Apple Time Machine is always available on the network. NAS devices are perfect for backup solutions so use them.
You can use Apple Time Machine for multiple backups in the following ways:

  1. Use external hard disk: Backup the first Apple computer with the Time Machine hard disk and then backup the next computer.
  2. Use network backup (NAS): Assign the network Time Machine for each computer on the network and backup. Nice, simple and always available when connected to the network.
  3. Use Apple Time Capsule. Apple TIme Capsule is build for this purpose but it is a bit expensive and not that feature rich as a NAS server. The Synology NAS servers are powerful devices that will outmatch Apple Time Capsules in many ways in my opinion.

So to summarize: If you got more than one Apple computer you can easily use the same Time Machine backup.