Terminologies of storage very important for VCAP-DCD

I have compiled this post from different positions (Duncan Epping), passionate about Valentin Vipin vExpert, vmware KB, etc. So the stock of credit goes to them.

I think this post will help the VCAP-DCD candidates for Design elements and objects of drag-and - drop.

VMware has introduced a new architecture for vsphere storage called PSA (Pluggable Storage Architecture). This architecture using plug-ins. This (PSA) is simply the name of the new concept.

Let's start with the native plugins of VMware.

The Multipathing (NMP) Native is the default module that uses ESX (from vSphere). It contains the two ATAS (storage array of plug-in type) and PSP (plugin path selection) plug-ins.

If your table is listed in the hardware compatibility list, VMware ESXi decided before (with the help of plugins PSP: VMW_PSP_FIXED VMW_PSP_MRU, VMW_PSP_RR) what paths multiple "algorithm" will be used. ESX will do natively: fixed, MRU, Round-Robin.

Note: * native vmware Multipathing algorithm = > fixed, MRU, Round-Robin *.

The NMP uses rules to decide who will serve as a storage array Type Plugin (ATAS) and Plugin access path selection (PSP) will be used. If you want to change these rules you can use 'esxcli' and you can find the rules in the "/ etc/vmware/esx.conf". For example the default PSP for the Bay EMC Symmetrix is fixed:

/ Storage/plugin/NMP/config [VMW_SATP_SYMM] / defaultpsp = 'VMW_PSP_FIXED.

What does ATAS?

The ATAS manages path fail-over, it's as simple as that. This of course will be reported back to the NMP, because the NMP is responsible to ensure a flow of e/s. The ATAS will monitor the health of a path and take the necessary steps according to the type of array. Nothing more, nothing less.

What does the PSP?

PSP determines which path will be used for a request of e/s, in other words the PSP addresses fixed, MRU and Round-Robin algorithm.

Keep in mind that the type of the PSP that will be used has already been preconfigured, it's not the PSP who decides that if she will be fixed or MRU, it's the NMP which decides this based on predefined rules above.

MPP

What's next? It would be a Plugin (MPP) of multiple paths. VMware NMP is built by vmware, on the other hand MPP is developed by sellers of paintings. EMC is one of the suppliers who have already demonstrated their MP. Example: EMC MPP is known as Powerpath for ESX.

-------------------------------------------------------------------------------------------------

Different types of storage and Multipathing policy:

Assets:-the storage system have two controllers and LUN (virtual disk or storage device) are accessible or host can perform i/o via the two controllers.

Active-passive:-host may have I/O to and from a unit number logic via a controller only (through active controller-owner - of the LUN and not through the other)

ALUA:-asymmetric Logic Unit Access is where the storage system simulates the function of assets (unit number logic is accessible via two controllers but alone will be the owner of it)

Example: EMC VNX 5300 is not really active/active table. It just a group of asymmetric access logical unit.

For this reason that ESX detect this EMC VNX 5300 as a storage ALUA and plug-in uses ATAS VMW_SATP_ALUA_CX.

If a storage system is active/active, active/passive or ALUA, vmware PSP may be FIXED, SRM or RR based on array type. The general rule is:

1. for an active-passive array, you will need to define the strategy of path (PSP) "most recently used". (The default PSP for active/passive storage devices is VMW_PSP_MRU). There is no path parameter with the MRU policy.

2. an active-active array should have the policy path set to "fixed". (The default PSP for active storage devices is VMW_PSP_FIXED).

Important: VMware does not recommend that you use VMW_PSP_FIXED for devices (table) that have the VMW_SATP_ALUA storage array type strategy assigned to them. This is because (according to my understanding) ALUA is not really active/active storage, so in this case, VMW_PSP_MRU should be used.

3. for both active/active and active/passive array, we can choose "round robin (RR).

The host uses an automatic path selection algorithm that runs through all Active paths connecting to arrays of active-passive, or through all the available paths connecting to the active tables. Automatic path selection implements through the physical paths available to your host for load balancing. Load Balancing is the process of spreading the i/o requests on the paths. The goal is to optimize the performance of flow as I/O per second, megabits per second, or response time.

VMW_PSP_RR is the default value for a number of tables and can be used with both active-active and active-passive arrays to implement balancing on different paths LUN.

Thus, the rule is to have chosen the PSP to the different array type:

For active/active - FIXED, RR table

For RR table - MRU, active/passive

For ALUA table (which is really a simulated table not really active/active, active/active)-MRU, RR

When storing ALUA, vmware SRM is also optimized / non optimized paths into account.

So in the case of a previous path optimized operation, I/O is shifted to the optimized path (which previously used before a failover to a path not optimized)

MRU switches to a different path when one of the following codes, meaning SCSI NOT_READY, ILLEGAL_REQUEST, NO_CONNECT and SP_HUNG are received from the table. Remember that MRU is not failback.

For active/active SAN, the policy path sets a single failover occurs when detection SCSI 'NO_CONNECT' code is received from the table. When the path back a return will happen.

As you can see, four against a single SCSI sense code. You can imagine what happens if you change MRU Fixed when it is not supported by the table. SCSI sense codes will be sent to the table, but ESX is not expected (NOT_READY, ILLEGAL_REQUEST, SP_HUNG) and a path will tilt.

Great write!

With regard to the PSP where it can be MRU or RR it is VERY important on review DCD that pay you close attention to the what the requirements are and what the instructions tell you to do.

Other then that, great work to consolidate this information

Tags: VMware

Similar Questions

  • whenever I open the installer from Adobe, it always say that "trying to connect to the server...". ». Please help me. I don't know what is happening, but my WI - Fi works very well. Adobe needs to know that this facility is very important for me

    whenever I open the installer from Adobe, it always say that "trying to connect to the server...". ». Please help me. I don't know what is happening, but my WI - Fi works very well. Adobe needs to know that this facility is very important for me!

    Please read https://forums.adobe.com/thread/1499014

    -try some steps such as changing browsers and disable your firewall

    -also clear the cache of your browser if you start with a fresh browser

    -check the file hosts for blocked entries https://forums.adobe.com/thread/1912777

  • I can no longer view source files in Firefox 6. It is very important for my work as SEO consultant.

    Under view I can no longer read the Web page Source file. SEO consultant, it is essential for my work. Please can you restore this functionality for FireFox 6.

    • Firefox > Web Developer > Page Source
    • Tools > Web Developer > Page Source
    • Right-click on a web page to open the shortcut menu and select the Source of the Page

  • BBM Q: very important

    Hello

    I used "BOLD" BB9900 for over 4 years and when I heard about the new BlackBerry I was happy to have BB Classes but he disappointed me because in the BBM, there is no (new category contact) which is VERY important for me.

    Now, I want to know in the future if this option is not yet or not, because it is not different between the OS10 BBM and BBM in another Smart Phone.

    Thanks for clairifying that. This feedback has been shared and this ability will be considered for a future version of BBM surveys.

  • When the VCAP-DCD and VCAP-DCA examinations for vSphere 5.0 will be available for registration?

    I'm a VCP5, I can't take the VCAP-DCD and DCA for vSphere 4.0 right? If the ideas when VMware will release the version 5.0 VCAP-DCD and DCA reviews? Thank you very much!

    Hello

    I asked the team of certification at VMworld on release dates and got a very vague answer. So far, there had been no mention of the beta exams VCAP nor is the same model released so I don't see it to become available before the end of February, which as noted Simon is a real shame that this means that all the VCP4 and VCAP4 holders must make the VCP5 in order to save to the Whats New course as a prerequisite. For the cost of the reviews, I think it's a real slap in the face to those who have spent time and money, get a number of certifications. Also there is no official decision of if you go the VCAP5 you will have your VCP4 improved to 5. So although validations who says that have been deleted.

    I booked my VCP5 because of this lack of news and ability to upgrade and I'm seriously considering not even reviews of VCAP5 because it takes a lot of time, money and effort to get to them and then VMware take forever to even keep up to date on how it's going or if there will be any sort of upgrade.

    I say VMware as a show of thanks for those who have spent so much time getting VCAP4 accreditations gives a 50% discount good for the VCAP5.

    I've built a whole page of resources that I use for my VCP5 if you are interested, here: http://thesaffageek.co.uk/vcp5/

    Also a page for the resources of VCAP5 here: http://thesaffageek.co.uk/vcap5-dca-dcd/

    Gregg

  • I just installed acrobat adobe 7.0 standard and everything seems to go well except it doesn't have the option of the typewriter in the section tool like my previous installation. This is a very important feature for me how this works?

    I just installed acrobat adobe 7.0 standard and everything seems to go well except it doesn't have the option of the typewriter in the section tool like my previous installation. This is a very important feature for me how this works?

    Hi timr22708473,

    Acrobat 7 is really an old version of acrobat & might not be compatible with your system configuration to features may or may not work.

    This is the reason why Adobe recommends always using the application in a consistent environment.

    Kind regards

    Nicos

  • VCAP-DCD after issue of DCA

    I just finished the VCAP-DCA, which has been a royal pain to study!  Took me 6 months and probably 300 to 400 total hours.  It was much longer that I wanted to spend, but I ended up finding it necessary to do so.

    I'm now toying with the idea of making the VCAP-DCD but want to know other people who took both who and the FLAK if they found that the DCD requires much study time or if it is less.  Just from reading the EHR Architecture, I guess it's a base much more has test because it is just done with diagram and drag and drop questions.  Without worrying about PowerCLI, SSH, advanced configuration settings, etc..  Looks like it would be more simple, but I just hope someone can check this for me before I consider getting serious about its pursuit.

    Hey Krenztor,

    I have a www.virtualtiers.net Simulator that will give you an idea of what will be the DCD.  Remember, it is more multiple choice review questions.  Also keep in mind the responses on the Simulator are not Gospel or a dump by any means, the tool must be used to learn about what the exam will be asked to you and how to use the design drawing area.  At the end of the Simulator is a Pack of study created by myself and the community.  It is on the lookout for the region you need to study on before attempting the DCD.

    The biggest problem with the DCD is it of design and very open ended.  The study material is not as cut and dry that the DCA is.  The DCA had a list of things that you need to out lab and know cold before the test, when it comes to design this is not so much cut and dry.

    I also suggest a look at the task force DCD google +.  There are a lot good information at this location.

    Good luck and happy student

    Hope this helps

  • VCAP-DCD research resources

    Hi all

    As most of you probably know approach the VCAP-DCD is a formidable task, the depth and breadth of knowledge and experience required is extensive.  There is a lot of material out there on the interweb, a lot of good community content generated as an individual making their own contribution.  I wish that the thread to be a space reserved for DCD all related resources.  I would be grateful if you could share all content, articles, links to KB articles related to DCD review and everything which may be useful also including general 'do' and and ' Don't ' advice.

    I want this thread can be all things related to the Resource Center for DCD review, and it's the perfect place to keep this information, the Community Forum.  Please don't be shy and start sharing.

    Concerning

    VFK

    Thanks Scott,.

    Here is a very complete link too VCDX Prep cycle 2 | TheSaffaGeek

    Don't you be concerned too much about VCDX in the title, is on the erect list just up, congratulations to this blogger.

    VFK

  • I noticed that the old dictaphone are now content 00:00, in Ipod touch iOs 9.3.1 - what I cn do to recover the content or to avoid this to happen in the future? Thank you very much for any information

    I noticed that old dictaphone now show content 00:00, iPod touch iOs 9.3.1 what I can do to recover the contents or to avoid this to happen in the future? Thank you very much for any information

    Try:

    -Reset the device iOS. Nothing will be lost

    Device iOS Reset: Hold down the On / Off button and the Home button at the same time for to

    ten seconds, until the Apple logo appears.

    -Try to import in our iTunes library on your computer

    -Reset all settings

    Go to settings > general > Reset and tap reset all settings.

    All your preferences and settings are reset. Information (such as your contacts and calendars) and media (such as songs and videos) are not affected.

    -Restore backup if they would be in a backup. See:

    Restore your device from an iCloud or iTunes backup - Apple Support

    Glitches to occur. Frequently import them to your iTunes library and frequently back up your device

  • Changed computers. Old HARD drive is now slave. FF is not find old settings and saved passwords. Very Important saved passwords.

    Hello
    I changed my computer. Essentially, the M/B, CPU, RAM, HARD drive, etc. I still have my old HDD and Mozilla is installed there. I have a lot of passwords saved on that Firefox. I started Firefox from here itself. Yet, FF can't find passwords and other things. They are very important because they are the passwords for the income tax, tax services, the VAT of various clients Web sites. I'm a tax lawyer. So, if I can't get these, I'm dead. Help, please.

    For passwords, you must signons3.txt and signons.sqlite

    See:

    The "Application Data" in XP/Win2K folder and the folder "AppData" in Vista/Windows 7 are hidden folders.

  • I need to convert some "very important electronic documents to Word 2010" How can I do?

    I have some very important electronic documents that I need to convert PDF to WORD 2010.  How can I do so without charge?

    The game, June 21, 2012 17:31:22 + 0000, Anita D says:

    I have some very important electronic documents that I need to convert PDF to WORD 2010.  How can I do so without charge?

    You need a program that can extract the text from a pdf file. He
    many of these programs, and you can find them with a search on the web.
    This is one of those programs that is free: http://www.a-pdf.com/text/

    But be aware that I have never used this program and cannot
    recommend or put you keep away from him. But you might want to try
    and see how it works for you.

    Ken Blake, Microsoft MVP

  • I installed Win 7, sis discovered downloaded illegally, ran XP and now how do I get rid of Win 7? Help, please! VERY IMPORTANT PLEASE AND THANK YOU!

    Okay, so I came one day at home to find Win 7 Ult on my computer. It turns out that my sister downloaded illegally, which I had no idea until it crashed my computer. He stopped working out of a reboot, I therefore had no choice but to run my backup version of Windows XP Professional. I wanted to keep the files of windows 7, I had some important docs ther, so I installed Windows XP under the C:\WINDOWS.old file and it works from there, and win 7 is in the C:\Windows folder. I have only one disk-37, 2 Go C, so I need all the space I can get. I don't know much about computers, but how do I get rid of Win 7 files which absorb almost 10 GB on my hard drive with Win XP works well? Win XP is activated and genuine. I heard someone say "Format the C drive", but then I read about it online and found that it could make my computer unusable! I don't know how to fix it! Please help me, it's very important that I have solve this problem quickly, I am sinking money in flash drives and CDs. help, please and thank you!

    In addition, my system is a Dell GX280 series, pentium 4 with 512 MB of RAM, or 502 a 37.2 GB C drive. It has been renovated and came pre-installed with Windows XP.

    The BIOS and Windows are not the same, you cannot make permanent changes to the BIOS settings only.

    When you format your hard drive it will wipe all information off of it (it's your personal files, Windows, everything, etc.), but your computer still won't turn.  Your can configure which devices to start the system turn off the first, so when we need to start installing Windows from a CD, you need to configure the BIOS first boot device to be the CD-ROM drive (follow thesteps to clean install xp).  You must ensure that your CD of Windows XP is in the CDROM drive ready to begin the clean install, and there should be a point when your system say "press any key to boot from the CD-ROM...".

    You can also follow the procedure here a clean installation of Windows XP: http://www.theeldergeek.com/clean_installation_of_windows_xp.htm

    Your email address was removed for reasons of confidentiality, but unfortunately I do not use my email address for support... only use this website :)

    --> I hope this helps! Please vote or mark as correct answer if it doesn't :)<>

    http://www.xinx.co.uk - my Web site | http://www.systems-and-solutions.co.uk - where I work


    Info from Microsoft about phishing . Information from Microsoft on the fake security software

  • I'm not able to remove my bitlocker to my external hard drive password. Please help me out, it is very important to me...

    I'm not able to remove my bitlocker to my external hard drive password. Please help me out, it is very important to me...

    Hello

    1. what happens when you try to delete the password?

    2. you receive an error message/code?

    3. have you forgot the password?

    The best way to remove the bitlocker password is to follow these steps.

    (a) connect your external hard drive in the computer.

    (b) click Start, click Control Panel.

    (c) while on the Panel, the icon find Bitlocker Drive Encryption , click

    (d) you will see all the partitions on your hard disk and their encryption status, whether encrypted or not.

    (e) on one that is encrypted, you will find an option to turn off bitlocker. Click on it and wait for the machine to decrypt.

    Check out the link:

    Microsoft's strategy concerning lost or forgotten passwords

    http://support.Microsoft.com/kb/189126

    It will be useful.

  • Need to recover a very important folder

    I had a very important folder called as 'mine.tst' in C:\Program\Yahoo\Companion\... "location. I had uninstalled yahoo functionality due to which the companion folder has been deleted. Therefore, also my important 'mine.tst' folder has been deleted. Please guide my how recover my mine.tst folder and its content files. I use Windows Vista SP2.

    Please let me know if you need more details.

    Hello

    This can help you recover a folder "deleted":

    http://www.Piriform.com/Recuva

    Get in touch with Yahoo for more information on the toolbar of their companion.

    See you soon.

  • Tried to password - protect folders (VERY important issues) and now cannot find/access them at all!

    That's what I had to do what I did:

    http://www.AddictiveTips.com/Windows-Tips/how-to-lock-and-password-protect-folder-in-Vista/

    Clearly, I clicked too much / the wrong thing, because these very important issues (for my work) are now completely inaccessible for me. This is not correct. I need them to work. Can someone help me please? (I feel like such a fool!)

    I tried restoring the system (twice) and nothing has changed. I have google and google to try to find a way to fix this, but so far have gotten nowhere! I'm a sort of panic... hoping someone can help me!

    So what (s) you refuse permissions on this folder? If deny you permissions to everyone, then of course your own username has been included in this group. Out of this is to start the computer with a Linux Live CD or USB key and the copy of the data in the files to external media such as a disk external hard USB or USB key. Linux will not honor Windows permissions. Then delete the files while in Linux. If all goes well, they are not system folders but are only folders you have created yourself. Then start in Windows, create new folders, copy your data to them. If you explain what and where are the files and what restrictions you want to give, we can help you to do this properly.

    http://Lifehacker.com/5504531/the-complete-guide-to-saving-your-Windows-system-with-a-thumb-drive
    http://www.howtogeek.com/HOWTO/17044/move-files-from-a-failing-PC-with-an-Ubuntu-Live-CD/
    https://help.Ubuntu.com/community/LiveCD
    http://www.Knoppix.NET

    MS - MVP - Elephant Boy computers - don't panic!

Maybe you are looking for