Akal Singh Sardar

akal@kernelsphere.com

Head - Oracle Technologies, Kernel Technologies

Akal Singh work as an Oracle Consultant & Instructor, He has over 12+ years of Oracle Implementation experience. He is an Oracle Certified Master (OCM). Expertise with Databases, RAC, Data Guard, ASM, Oracle Exadata, RMAN, Oracle Performance Tuning, Streams, Golden Gate, Security & more

Oracle 11g Grid Infrastructure & ASMDescribe the purpose and benefits of Grid Infrastructure & New features in ASM 11gR2. Understand difficulties in managing storage systems for growing databases, describe Oracle Database 11gR2 Grid Infrastructure, Components of 11gR2 Grid Infra, Purpose/Importance and Benefits of Grid Infrastructure. Purpose & benefits Using ASM Storage and what’s new in 11gR2 related to ASM.

Key Discussion Points

Enhancements in 11gR2 Purpose of ASM ASM Architecture Benefits of ASM What's new in 11gR2 for ASM?

Who Should Attend?Oracle DBA's, Oracle Developers

Oracle Storage Products: Automatic Storage

Management

So here we will be talking about 11g R2 release in Oracle in database we have grid infra and ASM, instead of directly going to the ASM concepts because ASM is acting as a storage here so but before we start with ASM direct

I can share few things with you.

Like let me start with the basic part generally we know about data bases I’ll be drawing here and I hope you are able to see for example this is my DB server right every organization small or big everyone want to maintain their database, database is nothing but collection of data maintained or stored digitally.

Now in this example if I’m starting my small business and I want to maintain a database for my application it’s a small kind of business and I want to have a database at the backend for it I can use my desktop why I need a server or even oracle that is the basic thing.

So yes any business organization is small to small right any small companies they can start their enterprise using a desktop they can install any software oracle or DBMS database software and maintain the data, so why the machine, a server or a desktop is needed they contain mainly 3 components 1 is CPU and the other one memory and disk.

When we talk about desktop and server architectures I bought a desktop with these 3 configuration in a desktop what kind of CPU will be available generally dual core quad core now a days so let me make it as a quad core right this is for my desktop but in case of a server the configuration will differ okay.

When you talk about memory how much RAM memory I can keep it if it is a 64 bit operating system OS and even you have a mother board 64 bit configuration in that case it can

support up to 8GB or 16GB of RAM what about the disk? In a desk top disks normally they are available in IDE with IDE controller or SATA controller.

IDE has become outdated now, now-a-days the desktops and laptops are coming with the SATA controller to which that IO operations happens on the disks generally if you open the desktop box and if you see there right the hard disk which is connected to the mother board connected through a cable that is something a 3inch white cable 1 end it goes to the mother board port that is nothing but your IDE port the other end is normally connected to your hard disk so IDE is a parallel architecture 1 port will be there in the mother board other side there will be 2 ports that means I can connect 2 hard disks right, generally the basic kind of mother boards in desktops or laptops specially desktops we’ll be getting what IDE with 2 controllers that means for each controller I can connect 2 disks the capacity is going to be of how much 4 hard disks I can have up to 4 hard disks. This is the capacity.

Fine it’s a small business I’m running here and I don’t need more than this I can start my business so this many companies or many small business they can run the databases on a desktop machine but here few challenges comes forward when they think about the future growth and their business model because now a day’s every business they are trying to give concepts or model called availability, they want to run their business round the clock even though it is a very small kind of business their data is not too much high and not in big volume but still they want to give the availability so here we are getting few factors round the clock they want to keep it nothing but it is 24/7 kind of environment every business.

The second big challenge starts when your data grows every business the data is growing now a day’s right any business data growth, just take out your mobile data is growing number of contacts are growing, messages are growing applications are growing in that so same every business will have a growth of data but challenges comes when data grows at this moment, I’m just taking an example as I started a small business so I can easily fit into this basic needs with the desktop configuration I have 4 hard disks but let me find out the size what is the size capacity I’m going to have in this volume so each hard disk what is the size?

In market you can find 500GB or even 1terabyte of hard disk now a day’s latest is 2 terabyte of hard disks are coming fine but let me take it as a 1 terabyte of hard disk and I can have up to 4 disks that is around how much totally its 4TB that means I can accommodate in a desktop up to 4TB of storage that is more enough for me 16GB of RAM and quad core what do you mean by quad core, it is nothing but 4 CPU’s.

As data is growing max up to 4TB I can use my desktop but another question comes here round the clock I want to run my business in those situations when I want to keep my database round the clock is my desktop models are they going to help or support me because desktops they are not designed to run continuously and here round the clock 24/7 means the whole day and night the server is up what will happen if I keep my desktop round the clock on it generates lot of heat and possibilities are there the components can damage.

In those situations problems are arising that machine can go down it can damage any component or there can be failures, because the desktop components are not designed to run continuously 24/7 take it the CPU, mother board or power or any other things something take your iPhone or any mobile now a day’s smart phones are coming up take any smart phone and continuously play for 1 hour 2 hour a video game what happens? Lot of heat generates battery drains fast if you play continuously every day that very soon you’re

ending the life of your mobile right.

Because the mobile is not designed to play the games yeah it supports that is secondary but they are not designed for it purely, same if I want to have a contiguously running of my machine desktop components are not designed to run contiguously.

So as looking at this is my requirement this is becoming a basic requirement for everyone 24/7 now a day’s what banking sector, online shopping, any reservation kind of environment many businesses you can take pizza hut even they are open 24/7 in that case their machine should be round the clock running so problem is that my desktop machines components they won’t support so what I want?I want a robustic component in the machine so I have to choose another kind of servers, what we have in servers, so whatever the component the memory or the disk or the CPU they are quality based they give the continuous life giving you the similar kind of performance whatever you have on the day one till the next last day, they guarantee you for next 3, 5 years that they will give the similar kind of performance without doubt that is the main thing.

I have to choose some quality based components if I want to run around the clock business that is okay but when my data is growing that is another big challenge right when data is growing in that case what I need more and more storage I can go up to 4terabyte but assume that very soonyou know jabong, flipkart this isonline marketing they started just recently within a year or 2 but now they have lot of customers across the globe right.

So same thing here if my business has grown extensively too high and already has filled up 4 terabyte and I need more and more storage then what a question comes in those cases what should I do I can’t add more disk in my available desktop it doesn’t support so I need to choose a machine which can accommodate or provide me more number of disksI can keep that is nothing but the servers.

If I talk about server, server can accommodate how many disks, server can have more number of disks if I look at each and every component I have only 4 CPU’s for processing right but if I want to have more number of CPU’s because as my data is growing, my business in growing is nothing but data is growing obviously the number of customers who are accessing this data they are also growing when number of people who want to access data they are growing they need more and more processing and I found that 4 core is not enough I need more than that then again I have to go for a server, soin server?

Basically it starts with the 4 CPU 4 core or even you can find 8 core 8 CPU’s not only 8, 16 CPU’s 32 CPU’s 64, 128 CPU’sthis you can go on, you can go on add more number of CPU’s oh really great but when we talk about memory how big I can grow RAM because in desktop I can only have only up to 16GB, no no you can grow here also right you can start with the 16GB, 32GB, 64GB, 128GBthis up to 1terabyte not only 1 terabyte but even 2 terabyte oracle X data right it gives you nearly 2 terabyte of RAM it’s too big, we’ll talk about the disk what kind of disks you have in the server you will be finding the SaaS disks they give you more performance more robust with low latency and performance issues right.

So SaaS disk how many you can attach thatdepends on the kind of mother board you are buying in that might be you can have 2 you can have 4 you can have 6 or 8this, no I want to have more than that because if my data is growing more than 4terabyte now it reached around 40 terabyte in case if it is 40 terabyte I need so many disks in that right that is about

the storage as data is growing I see the servers now a day’s server they are coming in a different models server they arewhich I have drawn as a blue diagram this isa tower based servers you can (( )) another kind of servers alsothis we call them as blade servers.

Tower servers isa big box so how many disks I can keep looking at the size might be I can accommodate based on the SaaS and controller and the number of days I can have 8, 12, 15 max again thatdepends on what type of connectivity you are giving if you are using 15 disks you can have max but still my question remains here same my data has grown more than 15terabyte then what should I do I have to buy extra disk keep it in a separate storage box and attach this disk storage to my server.

Somethingif my desktop or laptop hard disk got filled upwe dump our data we’ll attach a USB hard disk and we will try to move our data into that similar kind of thing I’m attaching another storage we call them array it is nothing buta box which contains set of disks again they are available in different configuration we can have 4, 6, 8, 12, 22this different disks capacity you will be getting this array.

Generally these storages shortly they are called as JBOD I hope the people who arestorage they will be knowing what is JBOD, don’t try to understand who don’t know its very simple what is JBOD?

It’s a just bunch of disks some extra spare addition disks I’m attaching to my server when I’m connecting what kind of connector I’m going to use for example I have some USB hard disk I want to connect to laptop how I will connect I need a port on my laptop or desk topI can connect the hard disk.

So these disks I’m connecting to my DB server so here you can use a SaaS controller here that inbuilt available SaaS control external interface you can use and you can connect if you don’t want that then you have other options also here, not only SaaS even if you want you can use ISCI interface or even fiber channel interface.

They provide you high data transfer rateserver to the storage somethinga USB 2 and USB 3 how we got different interfaces again the speed varies there similar kind we have ISCI and fiber channel connectors.

So using this I’ll be connecting to my storages but there is one more problem here assume that I have upgraded my number of CPU’s4 because I’m using a server I came to 16 CPU’s or 32 core CPU’s, processing will be done faster and I added few more extra disks on my JBOD extra storage is attached to my server but whenever IO needs to be done who need that data CPU need the data so it sends a request to the disk.

So in those cases the request was sent by the CPU passed by the SaaS controller if you are using FC controller or ISCI, so FC or ISCI they are going to pass this request to the storage, so the storage also you will be having a controller which is responsible to perform the IO’s on the disk take this data bring this data and give back to the server.

So that means my CPU is completely busy doing the IO’s on the storage passing through this channel example I attached a USB 2 hard disk or USB 3 hard disk to my laptop when I want to copy a file will it won’t be using my desktop or server CPU to do a copy there right perform a IO on the disk yes my CPU is doing a IO on external disk same way my server CPU’s are now becoming busier because of doing more and more IO’s on extra disk that is

the one big challenge.

Then slowly what happened so instead of making your data base server CPU’s loaded now a day’s the new kind of storages are introduced so in which you will be having the number of disks same number of disks available and even you will have few more other additional components in there example you will have your own operating system it contains its own operating system it contains its own management software and even it contains its own CPU right and even they will have their own memory.

So this way whenever server want any data now server CPU will be sending the IO request to this local storage this management server with the help his own local CPU it will perform a IO on the available disks, takes the data brings and gives backs to this database server CPU now mean while my data base servers CPU can do other activities while the storage CPU is performing IO’s.

So now we got 2 types of storages here 1 storage we have only set of disks IO operations are taken care by my server CPU we have another set of storage disk it contains its own local operating system management software CPU’s and memory what will happen here my database server is sending that request to this local external storage this management software with the help of this local CPU’s it is performing IO on that disk and sending back data to the data base server.I have good enough time while the IO operations are happening here I can perform some other activities I can work with many other activities.

This 2 types of storages I can name then generally they are called into 2 more different ways one is called as intelligent the other one is called as a non-intelligent, non-intelligent is nothing but they don’t have this OS management, CPU and memory they are simply desktop (( )) attached to the server shortly we call them as a just bunch of disk or JBOD and the intelligent storages they contain their own CPU memory and software.

Now the connectivity yeah I can use any of those so I have 2 choices ISCI or FC what is the speed, data transfer the ISCI can do? ISCI is available with 1gigabit to 10gigabit controllers are available when you talk about FC 2gigabit, 4gigabit, 8gigabit something and even 16gigabit is the max speed for this one.

So that’s why in the production people use FC fiber channel with different kind of cable fiber channel cabling through which the servers access the storage these kind of storages or these kind of infrastructures shortly people call them as a NAS/SAN.

Network attached storage and storage area network as data is growing day by day we need more and more disks in data base server and when I have more disks this so I’m getting different kind of storage non intelligent and intelligent storages and I’ll be forming a environment called as a NAS or SAN architecture, multiple machine or single machine connected or storage connected over the network to the machines.

Here one more thing the database point of view if we look we have few challenges, so here we have a topic called grid infrastructure and another is ASM, first let me try to understand the ASM because grid infrastructure is a software they newly brought it next side by side, if you look at my database server now I upgrade myself to the server I have more number of disks I can accommodate more number of disks locally within a server or extra few more disks I can have in the extra storages.

So I got so many disks now how you are going to place data across the disks now tell me what is the size of each disk maximum of 1terabyte but each disk is shown as a partition a mount point and problems are coming here if I can have a mount point of only 1terabyte then if I have this 40, 50 disks because 40 terabyte data means around 40 disks I want, so 40 mount points will be created there who will manage them might be on one of the mount point I have more number of files compared to the other mount point these type of challenges are raised.

Earlier DBS used to do IO tuning it means they try to move data frequently used or accessed data to some other different devices and storages why they want to simply balance thee data across the disks balancing of data right, so here balancing of data is required for this how I can do there are few software available called as a volume manager because each disk is a volume manager so I have to start using a volume manager for them.

I’ll take one example in the ASM, here assume that I have brought one server containing 4 hard disks in them I have 1, 2, 3, 4 hard disks in them what is the size of each hard disk I bought each hard disk of 120GB, what is the sum ofthe disk size it became now? It became of 480GB, I want to create a C drive I selected 1 disk created a partition C drive with 20GB, done.

How much space is available in first disk? I have nearly around 100GB so I want to create D drive here can I create D drive with the remaining 100GB, yes you can create 100GB.

Now how much space left in the remaining disks remaining 120 three times that is around 360GB I have now here my basic requirement what is that I have 360GB, so out of this 360GB now I want to create E drive with what size? E drive I want to have with 160GB out of 360GB or better let me make round figure 200GB or let me better take complete 360GB and create D drive can I do this?

Generally with the default operating system tools and utilities no, because in windows if I go to disk management I can seethe disks are shown in blue color right click and create partition what is the partition size max you can create nothing but the size of the hard disk what is the size? It is of only 120GB so I can have a partition of only 120 not bigger than that.

But I want to have E drive here 160, 200 or let me take 360GB is that possible? By default no operating system says no you can’t do that but this is my requirement then if you want this 360GB then you have to go with another software called as a volume manager.

Volume manager is going to allow you to create E drive how? By selecting one or multiple disks grouping them as a single logical entity here so as a end user I see it’s a E drive right

its only 1 drive for me but down the line it contains multiple disks who is doing this all? Volume manager in that case I should use volume manager to group multiple disks and see it as a single logical drive this is single logical drive.

Let me ask volume manager, boss is it only the one feature are you providing? No no we have few more features available with volume manager what are those features available extra features you are providing with volume manager, yeah I can get availability and performance with volume manager how it is possible? With the name called Raid with the help of Raid I can avail this benefit, we have different raid right raid 0, raid 1, raid 2, raid 3, raid 4, raid 5 there are so many different raid concepts available.

Let me take the widely used that is raid 0 raid 1 and raid 5, if we talk about raid 0 here what is raid 0 means raid 0 is nothing but stripping what is raid 1? Raid 1 is nothing but mirroring and raid 0 is stripping okay so raid 0 stripping and mirroring what do you mean by stripping?

So whatever data you write into any of these disks it gets stripped acrossthe 3 example 360GB I created this E drive selectingthe disks I’m writing 15MB file so 3 time 5 MB it was written tothe 3 disks example I’m writing A B C, so A is written here example I’m telling the content B content is written here somethinga C content means data is stripped acrossthe disks this is actually a big challenge for every (( )) previous version when they are using the normal file system they need to monitor in which disk right in which drive we have more number of disk who are doing lot of IO’s they try to differentiate them and try to move some of the highly used disk to some other drives to balance the IO operation amongbut here automatically data was written tothe disks parallel this is improving the performance so this is a indication for my performance here I’m gaining performance in this.

So I have option here performance and availability benefits how? With the name called Raid, raid 0 is nothing but it is giving me the performance for me it is the performance symbol what about raid 1? Raid 1 is nothing but mirroring means I have a question here in case one of the disk is failed can you access my content A B C example the last disk got collapsed or failed so I can’t access the C content it is unavailable to the user, data is not available.

In mirroring what happens? Whatever content written to 1 disk it is written to another disk A B was written to another disk B C was written to another disk, C data is getting mirrored why? In case example the last disk got failed still I can access my A B and Cthe first one right data is availablethe other disk and still my data base can run users can still work even if one of the disk fails, so it is giving me the availability kind of feature by doing mirroring data right we have raid 5 what is raid 5? It is nothing but parity.

Parity means example your bad luck multiple disks are failed in that case more than one disk fail example 2 in that case can you access data no so what happens here A A another A copy is written in a compressed order in another disk, B and B another B was written in a compressed order in another disk C and C one more compressed data was written to another disk.

Why even though both are lost still I can get the data that is nothing but raid 5 kind of architecture so this is also giving me the availability so I got performance, availability with raid 0 1 and 5.

So lookshere people are started using this volume manager why because their number of

disks are growing manageability is becoming difficult performance problems are raising so people are started using volume manager to group multiple disks as a single logical entity and gain performance and availability on that one simply it looks likes a giving a business, when oracle database is growing it is giving a business when oracle database is growing its is giving a business volume managers so oracle they came with a concept here saying “boss why should I give business to them? Let me have my own business” so they came with a new component called ASM “Automatic Storage Management”.

So what it will do? ASM is claiming it can givethe benefits and feature whatever the volume managers capable of let me compare here as a volume manager here I created E drive can I do the same thing with ASM as oracle says yes you can get that with ASM I can create a single logical entity by grouping this multiple disks what we call it shortly? We call it as a disk group.

Here we call E drive D drive and here in ASM we call it as a disk group by grouping multiple disks as a single logical entity is it only one in ASM do we have this performance and availability features yes we have those so by default ASM disk groups perform data stripping means data will be stripped acrossdisks means by default I’m getting the performance here, so you don’t have a choice that you uncheck or check this stripping by default internally oracle will stripe data acrossthe disk in a disk (( )) okay that is the situation.

What will be the availability that means by default I’m getting the performance okay accepted but what about availability? Yes you can get the availability you have a choice you have to choose the options called redundancy if I go with the redundancy I have 3 choices in this what are those?

One let me name it as a if you want mirroring yes I can get the mirroring that is called normal, what is normal it is samethe raid one it is nothing but mirroring here I can see so normal will maintain how many copies here normal is going to maintain 2 copies sameraid one so what is the other option I have one more option called high what high will do in high you can have 3 copies it is similar to raid 5 okay.

So we got normal 2 copies high means 3 copies in redundancy no I don’t want any mirroring because in a mirroring double or triple the space is getting wasted, because it will maintain multiple copies I don’t want that in that case you can here external, external is nothing but I’m selecting the option called none.

Oracle didn’t define anyone directly none it is saying external meansthe ASM point you don’t do any mirroring I will manage or I’m managing the redundancy externally at the storage level or with some other software so I’m saying ASM not to do any mirroring there is somethingdisabling the mirroring right.

So looksI gotthe features whatever the volume manager is giving ASM is also going to give me grouping the disks and giving me the redundancy and performance they are the benefits features that are available with the ASM. Now it’s your choice you want to go with a volume manager or ASM.

in this situation if I’m building any server and I want to go with a volume manager whatis required for me? One is operating system layer I need to install OS in the server then if I’m planning with a volume manager I need here what volume manager also, this volume manager is going to manage the disk example I have a storage connected to my server I got so many disk in the storage multiple disks I have so what should I do for multiple disks, I want to group this disk as a single logical entity so with the help of volume manager I’ll be grouping these disks into 2 I’ll create this one as a 1 group the another set of disk I’ll be creating as another group let me call them as disk 1 partition the other one as disk 2 partition.

Generally what we see so how I group this disk and store as a single logical entity with the help of volume manager then on top of this I’ll install oracle software oracle home getting shortly OH and I will run my oracle instance nothing but your ORCR what it will do it will be accessing data accessing my ORCL instance placing data in disk one or disk two but down the lane volume manager grouping multiple disk as a single logical this is one model.

But if you are coming with ASM, ASM is an instance and here I don’t want to use volume

manager so in that case if I don’t want to use volume manager I’m removing this part I don’t want to use volume manager and I want to use ASM instance simply you can configure one more instancethis home called as ASM instance and you can use this ASM instance to group multiple disks. So in that case what name I’ll be having here I’ll be getting the names here disk group names so I’ll be using here data disk group and FRA disk group any name data 1 or data 2 yes that is also good I can use any name here data and FRA any name.

So in this data and FRA my oracle database is going to keep their files disk one disk two D drive E drive samehere disk group 1 disk group 2 could be any namedata and FRA who is managing this ASM.

So ASM is an instance, instance means background processes and memory so now this ASM instance will manage this number of disks grouping them and mounting them but here startingoracle 10g this is an example I’m talking about 10g still here I’m using a single oracle home and 2 instances one is ASM and another is ORCM but whenever I want to apply a patch normally we will find lot of issues with ORC or oracle database we want to apply a patch read me says I need to stopinstances runningthat home if it is a common home that means I need to stop my ASM also right those are the issues coming up here.

So I need to take down the ASM here and apply the patches so every time my ASM is going to do nothing butthe disk groups in the complete storage is going down that should not happen many dependences are there after applying patch oh no what happened I applied a wrong patch here instead of applying 101 I applied a 102 I corrupted (( )) can I bring my ASM up no I can’t do that means interrupting the operations of my ASM why? Because both are using a common home these kind of basic problems we call them as a single point of failures arises.

So oracle gives a recommendation here what recommendation? Oracle is saying why are you using the same home for both of them right then better use a separate home for ASM separate home for oracle use them separately.

So we have 2 oracle home that means in 10g on top of OS I’ll be installing 1 oracle home for my ORCL the another oracle home for ASM generally we call it as what we call this home as ASM home the other one we started calling them as oracle home so we need 2 homes here this is recommended why? Whenever you are applying a patch and ORCL only this home is getting effected still my ASM is up not effected the other databases if anything available in your storage or server.

Now we got 2 homes butthe 11g onwards what they made? They made in a server on top of the operating system you are going to install only one software now that is called as a grid infra, grid infrastructure is a oracles provided software because if you look here the same oracle software installed twice one directory through which I’m running ORCL the other one in a separate directory through which I’m running the ASM instance.

So when you install the grid infra it is available in 2 modes, here you have 2 choices with grid infra while doing the installation you have one stand alone installation the other one is called as a cluster installation in a cluster installation what I will get I will get oracle cluster software plus ASM. In the other one standard addition what I will get I’m going to have the ASM instance means if I look at this ASM home in the first diagram in 10g it is the same oracle software I have installed in a separate directory but do I really need that sequel

loader or there are many more utilities of oracle engine not needed I doesn’t need the complete software I had only few libraries bandwidths which will help me to run this ASM instance so those penetrates libraries are taken and came out with the separate software called grid infra but what extra it is doing just a name change no no.

Oracle says I’m giving you something extra with ASM what is that we have oracle restart oracle restart is one more component they added what oracle restart will do? Samethe cluster ware right oracle cluster what is the purpose of oracle cluster it gives you the availability means whatever the services running in the server in cluster if they are registered with the cluster and if they are failed are abnormally went down automatically those services are restarted back by cluster that giving you availability.

Similar kind of component those services they added into single instances also this is a standalone machine in a single instance machine they added the similar kind of functionality with a name called oracle restart. So oracle restart is going to bring back your services which ever registered there but prior to 11g we don’t have this how we do? We are writing our own script or our own method to bring up those services.

So grid infrastructure we got a software in which I can have my ASM grid infrastructure consists of ASM software for ASM plus cluster ware installation again the same grid infra available for standalone alsoI will get ASM plus oracle restart.

For example these are the services you can see here oracle high availability service demands and many demands these arehelping right or giving the concept of oracle restart how to know what are the services registered with oracle restart we have a utility called CRS_start minus T option I can try it shows me here right 11g we have a command also CRSCTL status of resources minus T in a tabular format minus T is nothing but table format it is showing me table format whatI have here ORCL database and everything available here.

I’ll show you one this oracle restart is managing let me take the first command what is the CRS_start minus T and let me keep it in a loop, loop means I’m going to close this with the codes watch – n is a utility command which runs the commands what are the commands you are mentioning in this code right it runs repeatedly okay let me enter you can see the time on the top in this putty here it is running. So every second it is showing me the output let it be I’m opening one more duplicate session here logging as oracle and oracle I see here ORCL is running fine let me kill this instance 3137 on the above I can see the status pick an offline but what is the target saying? it is saying still online that means it should me always online but it went abnormally down it was detected by oracle restart and those services are trying to bring back your data base instance up. So just wait for a couple of seconds now you see that it was back and if I again just type ps grep pmon I see that pmon my oracle instance is up this was not there in previous version this is the benefit of grid infrastructure on a standalone server.

That means if I install grid infrastructure on a standalone I will get the ASM instance plus oracle restart component which gives me the availability the same grid infrastructure software is there if you install it for cluster it gives me the cluster components cluster services plus ASM so ASM by default available in both the instances in (( )) we have cluster in single instance standalone we have oracle restart that is the one okay.

So let me take few slides here, so you have a choice on top of operating system you can use volume manager and some file system cluster file system or better use ASM and directly you can store your data base in the ASM right ASM is the parallel solution given next to the volume manager.

ASM disk groups while creating components disk groups you have a choice you can define here what kind of redundancy you want? You want normal high or external normal means 2 mirroring copies 3 mirroring copies and here no mirroring you can choose that mirroring.

ASM Data Management

What more we have? When you go with a ASM disk group by selected few disks here and created one disk group what is happening I can see here data was stripped across the disks it’s not the older scenario, in the older scenario this is the situation data will be are hits will be happening always on specific kind of disks, but now data was divided across also disk are going to give a life and performance to you that is another benefit of this one.

Should You Use ASM Mirroring Protection

So disk mirroring how it happens? I can see in this so whatever data written to one disk it is mirrored in the another one whatever is written here it is mirrored in the another one whatever is available mirror in the another one, if we see one of the disk fails still I can access the 3 colors 1 2 and 3 but immediately there is one more thing happens here called rebalancing what it will do once the disk is failed or offline immediately it will crosscheck with the data it will check that for this do we have a mirroring copy no it will maintain in another disk do we have a copy for the other one no it will maintain a copy on this one why after sometime again if another disk fail still I can access data a one available disk giving you more and more availability in case of a loss of disk right this is the mirroring concept in ASM.

So I can have a single ASM instance running using which I will create a disk group 1 disk group 2this selecting multiple disks in them and in this disk group nothing but a D drive or E drive I can say in windows are disk one or disk two here I’m calling them as a group A and group B that’s all. I can keep multiple data bases data in those disks yes D drive and E drive I have so how many data bases I can keep in that? I can create many data base as many as I have the space available in them and I can store same kind there is only one ASM instance which can serve this multiple disk groups and manage and multiple data bases they can store their data in these disk groups now.

ASM Key Features and Benefits

ASM key features and benefits, what is the benefits available stripes the file rather than volumes data stripping will happen in the file level provides redundancy on the file basis enables online disk reconfiguration and dynamic rebalancing, the disk is filled automatically rebalancing happens nothing but again data got balanced across disk this is called rebalancing this is automatically happens online disk reconfiguration and dynamically rebalancing.

Reduces the time significantly to resynchronize the failure kind of files it is a cluster avail it is a rack environment or a non-rack environment it understands everything is automatically install as part of the grid infrastructure.

So ASM scalability if you are going to use ASM as a volume manager, so I can have 63 disks groups in a system 10000 ASM disks 2 terabyte maximum storage for each disk 4 terabyte but this is x data kind of storages live it 40 exabyte maximum storage file system so ASM files has limit I can have up to 140 petabyte external redundancy is 222 byte your storages whatever disk groups.

So I have group of disks I have 2 groups here group A and group B multiple disks we have views in ASM through which you can find the information how many disk groups I have I can find v$ASM_diskgroup I can see what disk groups I have so in each disk groups how many

disks I’m using I can find v$ASM_disks in each disk group I’m placing some file data file or some data base related file what file those are I want to see? v$ASM files who are the clients who are accessing them? The disk groups I can view v$ASM client his some views are there where you can view this information.

So grid infrastructure is a software which provides you the 2 components 1 is the ASM and oracle restart in a standalone machine and ASM lot of benefits is the similar comparison to the volume manager giving you redundancy performance and availability kind of features.

What is ASM power limitThat is a parameter in ASM which will help while doing the rebalancing I shown a diagram one of the disk goes offline automatically the data which is not available in another disk will get mirrored means you get a copy so that rebalancing is done by 2 process 1 is called (( )) another is called ARB (( )) rebalancing processing another is ARB agent for rebalancing so by default you will have only one ARB who is responsible to actually move the context one to the other nothing but copying the content one to other whenever you do add a disk or a disk offline or anything automatically rebalancing happens there. So by default you have only 1 ARB who do this movement of data or copying data that was decided by this parameter ASM power limit by default ASM power limit value is one nothing but only one ARB how many you can increase maximum up to 11, but having more ARBs will take more load and more CPU and IO because process are trying to balance the data.

In ASM normal is nothing but R1 but R1 is nothing but

mirroring but you said that mirroring is not present in

ASM give this as clarityNormal redundancy is same raid 1 yeah mirroring is available in that if you don’t want mirroring in ASM you can choose external, external means no mirroring we have 3 options external, normal, high external means no mirroring normal means mirroring 2 copies high means 3 copies mirroring again.