Oracle ASM Mirroring and Failure groups.

Oracle ASM keeps redundancy quite simple by providing only 3 options. you can choose to have no redundancy or mirroring provided by the ASM instance. This is the ‘External’ option and assumes that you are handling mirroring somewhere else perhaps through hardware raid on your storage network.

You can chose ‘normal’ 2 way mirroring r ‘High’ for 3 way mirroring.

This option is set for each disk group and can be different for every one.

Basically, the redundancy level determines how many disks you can afford to have fail before the disk group is dismounted or data loss occurs. With external mirroring, you can’t afford to lose any disks whereas with 3 way mirroring, you could lose 2 disks and there would still be one copy available.

With normal RAID, the level of mirroring is set for the disk (or disk group). ASM gives you a more granular level of control. For example, it is possible to set different mirroring levels for different files on a single disk group.

When data is created or an extent is allocated, ASM creates a primary copy and a mirrored copy. these copies are distributed across failure groups so that losing a failure group completely would not in and of itself cause the loss of any data.

You cannot change the redundancy levels of a disk group once it is created. If failure groups are not specified, ASM places each disk into its own failure group (unless the disk group contains Exadata cells.

 

 

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Cleaning up a failed Oracle 11g grid infrastructure install.

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Unfortunately, the installer or more specifically the root.sh script for the Oracle 11g grid (Clusterware) installer can be very flaky.

 

If it fails and you need to fix something or rerun it for any reason, it will fail the next time if you have not cleaned up the install by de-configuring CRS. I also like to wipe the installation off altogether and restart from a clean base. Here are the steps.

/u01/app/11.2.0/grid/crs/install/rootcrs.pl -deconfig -verbose -force

/u01/app/11.2.0/grid/crs/install/rootcrs.pl -deconfig -verbose -force -lastnode

At this point, you could rerun root.sh (after you have fixed the problem, but if you have closed the installer or just want to restart from a clean base then continue with the steps below.

 

Get the oracle home from the inventory then delete them both

 cat /etc/oraInst.loc

cd /u01/app/oraInventory/ContentsXML/

cat inventory.xml

Find the Oracle home

Remove it on all nodes

 rm -R /u01/app/11.2.0/

Also remove the inventory

rm -R /u01/app/oraInventory/

rm -R /etc/oracle

rm /etc/oraInst.loc

rm /etc/oratab

rm /usr/local/bin/dbhome

rm /usr/local/bin/oraenv

rm /usr/local/bin/coraenv

Then change the ownership of the /u01/app directory:

chown oracle:dba /u01/app

 

You could stop there but if you really want to wipe the slate, you could delete your ASM disks  and recreate them fresh before the next install.

 

Delete your ASM disks on node 1

 oracleasm deletedisk DISK1

oracleasm deletedisk DISK2

oracleasm deletedisk DISK3

oracleasm deletedisk DISK4

.

.

.

 

On all nodes

oracleasm scandisks

/usr/sbin/oracleasm exit

 

Now give your node a reboot and you should have a clean base from which to start another install.

 

Companies in “Boring” Niches Creating Great Content

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If you are going to be online, and you need to produce content. it is as simple as that. One of the big problems that many non info based businesses online raise is that their topic is boring or that there is nothing to write about. This is almost always wrong. Take a look at how these businesses are tackling the problem creatively. http://www.seomoz.org/blog/companies-in-boring-niches-creating-great-content

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Anatomy of a Successful PPC Ad

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What are the factors that determine a PPC ads success or failure? What factors should you work on to improve your ads effectiveness? This article focuses on the fundamentals, not things like keyword selection or improving quality score, but the factors that make a really good ad that makes people buy or click. http://searchenginewatch.com/article/2183894/Anatomy-of-a-Successful-PPC-Ad

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How to Start Link building for a New Website.

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It can be confusing when you have a new website and you want to start link building. There is a lot of conflicting advice out there about what type of links you should get and how fast you should get them.

Before we get started and get into the different types of links, I want to make sure that you are using 2 very useful and free tools. Google webmaster tools and Analytics. They are virtually impossible to beat for the price and give you important information about your links and keywords. More importantly, they keep you up to data about how Google views your site.

Now, lets talk about links…

Directory Links

These used to be the first thing you did when you had a new website. Unfortunately, they have been spammed and abused so much that most of them provide no value now and there is even rumours of Google de-indexing large numbers of them.
It may still be worth getting a link from a high quality directory like BOTW, but don’t spend much time on this type of link.

Blogroll links

These are a mixed bag. Theoretically, these should be great as they are a big endorsement from the webmaster of the site. In reality though, they have been twisted, abused and spammed to death.
I would still say that you need to take it on a case by case basis. For example, if a site has a handful of great sites that are totally relevant in is blogroll, you may want to get in their. If however, they have 50 sites to junk sites; run a mile.

These fall into the category of site wide links, so see that section for more info.

Site wide links

On first glance, these look amazing! Instead of getting 1 link, on a 50 page site, you get 50 links. Awesome! Well, not exactly. Google understands what is going on and only counts them as 1 link. Think of it as each site only being able to give 1 site 1 vote.

I don’t think there is anything inherently wrong with them, they just aren’t as good as they seem and they clutter up your link profile.

Comment links

These are one of the most used link types by black hatters. Tools like Scrape box can generate thousands of junk comments and links totally on autopilot and they used to be quite effective but aren’t now.
Again, there should be no problem if you are posting genuine comments that add value, but you are relying on Google being able to separate your genuine comment from all of the junk. that’s a risk that I am not that keen on taking.

Social Media Profile Links

Generally ‘nofollow’ but a great way to start your link building anyway. This is where you put a link in yout profile on Twitter or Facebook etc. Linking froma quality profile isn’t going to hurt and might get you traffic from the social site.

Editorial Links

The kind of links that you get without asking when you are putting out top quality content and showing it to people. These are probably the best kind of links that you can get.
You can increase the chances of getting these by networking.

Guest Post Links

These are a close second to editorial links. Basically, you either write a great post and ask a webmaster to post it to their site or you ask a webmaster what they want and write it for them. You are getting your name out and adding value to a site. this also increases your networking range if you maintain the relationship.

Resource links

Oftentimes, older sites may have links pages or resources pages and it can be worth asking the webmaster of these sites for a link. (If your site is a good match)

Leading on from that, you can ask anyone for a link. Just coming out of the blue with that request is going to get you turned down a lot but its only an email!

Legitimate Business Links

Industry directories, local business listing, chamber of commerce etc. can all be great links.

Local links

Google Places, Yahoo Local, Bing business. these can bring in traffic and increase your exposure.

Reciprocal links

If you are doing this for reasons other than SEO, then there is nothing wrong with it. From the point of view of SEO though, they don’t carry much power.

I think you can probably gather from my descriptions, which links I think you should aim for.

Business listings, local links, resource links, social media profile links, guest post links, and begged-for links. Then go get your BOTW link and go back to the start.

Consistency is the key for most sites, that and focusing on putting out great content.

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