What are the differences between failover modes on a CLARiiON array?
Posted by thewriter in EMC Clariion on June 28th, 2009
Written by diwakarnitw on Jul-22-07
From: storageknowledgeshare.blogspot.com
What are the differences between failover modes on a CLARiiON array?
A CLARiiON array is an Active/Passive device and uses a LUN ownership model. In other words, when a LUN is bound it has a default owner, either SP-A or SP-B. I/O requests traveling to a port SP-A can only reach LUNs owned by SP-A and I/O requests traveling to a port on SP-B can only reach LUNs owned SP-B. It is necessary to have different failover methods because in certain situations a host will need to access a LUN on the non-owning SP.
The following failover modes apply:
Failover Mode 0 –
LUN Based Trespass Mode This failover mode is the default and works in conjunction with the Auto-trespass feature. Auto-trespass is a mode of operation that is set on a LUN by LUN basis. If Auto-Trespass is enabled on the LUN, the non-owning SP will report that the LUN exists and is available for access. The LUN will trespass to the SP where the I/O request is sent. Every time the LUN is trespassed a Unit Attention message is recorded. If Auto-trespass is disabled, the non-owning SP will report that the LUN exists but it is not available for access. If an I/O request is sent to the non-owning SP, it is rejected and the LUN’s ownership will not change. Note: The combination of Failover Mode 0 and Auto-Trespass can be dangerous if the host is sending I/O requests to both SP-A and SP-B because the LUN will need to trespass to fulfill each request. This combination is most commonly seen on an HP-UX server using PV-Links. The Auto-trespass feature is enabled through the Initiator Type setting of HP-AutoTrespass. A host with no failover software should use the combination of Failover Mode 0 and Auto-trespass disabled.
Don’t Just Rely on the Google and MSN Toolbars For Popups and Spyware Protection!
This article describes the disadvantages of relying on freeware to block popups, in the wider context of adware and spyware protection.
Adware are commonly defined as any type of software which plays, displays or downloads advertisements on computers. Some adware are programmed to invade the privacy of the users and are commonly referred to as spyware. These programs obtain then share personal information about the users, without their knowledge or consent.
Adware popups have become a common irritation for most users and many are now looking for free ways to disable them. The preferred solution for many users is to rely on the popup blocker function of either the Google or MSN toolbar. Most users do not realise the link between popups and spyware, very few take the right steps to protect themselves and the majority of users concentrate on just blocking popup ads. Yet experience shows that both the removal of adware and spyware, as well their prevention are necessary steps to protect users privacy, preserve the integrity of their systems and enable a pleasant on line experience. This contrasts with the false sense of security which can result from just relying on blocking popups. This is because the most serious problem with popups is not just that they are “irritating”, but rather that they are often the symptom of spyware infection, as is demonstrated by popups appearing when users are not even connected to the internet.
Changing the browser settings is free and a step in the right direction
Blocking adware popups whilst browsing is easy enough. Changing the privacy settings so that popups can no longer appear on screen can be done as follows:
· Select Control Panel in your computer
· Click on the Internet Options icon
· Click on the Privacy tab.
· There is a box next to “Turn on Pop Up Blocker”.
· Tick this box and you will block adware popups.
Once the settings have been changed, users should adjust the privacy levels on their computer. Another option is to download the MSN and Google toolbars. Security when browsing the Internet can be improved when using these toolbars. For more information, click on free popup blockers.
But, what about achieving complete protection? What is the bigger picture for most users?
Unfortunately, most users simply focus on blocking popups then forget that their computer is probably infected with adware and spyware. Popup blockers such as those offered by the Google and MSN toolbars, whilst useful are just dealing with one aspect of privacy and system integrity protection. For more information click on block spyware.
At this point, it is recommended to consider more broadly, how to protect the users’ privacy as well as preserve their computer integrity from spyware and adware attacks. In addition, users should run the latest version of their anti-virus software, then remove the adware and spyware on their computer, using appropriate tools. Adware and spyware are often downloaded without the users being aware of them.
Getting rid of adware and spyware is easily achieved with the most popular adware and spyware removal programs, which can also block popup ads. The most popular adware and spyware removal programs rely on research teams to detect and review the latest known threats. These software are frequently updated. Adware and spyware removal software can also block malicious programs . This approach is therefore more effective than the reliance on free popup blockers. For more information click on adware spyware removal.
Just How Good Is Registry Fix V7.1?
The increasing range of computer threats and their negative impact on computer performance, is leading to greater intensity in competition between registry repair software vendors. This article shares the results of one of the latest the review of Registry Fix V7.1. Tests were carried out by our testing team (Click on registry fix review for more information).
In the main, Registry Fix has been one of the most popular solution Clickbank (largest digital market place), and achieved over 13 million downloads. We wanted to establish if Registry V7.1 was actually as good as the software vendors make it.
How To Speed Up Your Computer With A Windows Registry Repair
When your Windows computer starts to slow down the first suspect is a faulty registry. Windows registry repair used to be difficult.f you didn't know how to edit the mysterious code in the Windows registry by hand, then you would take your computer to a shop, leave it there for days and hope someone could work it out.
Even though the registry is huge, it is well structured which means it is perfect for repairing with an automated registry repair software tool.You will be surprised how easily you can perform a windows registry repair yourself.You are, in fact, able to use exactly the same automated tools the shop uses!
If your computer is running slow, slow booting, slow loading programs or crashing frequently then I would begin first with cleaning or repairing the registry because a bloated or corrupt registry is often the cause of these problems.
Because of all the software installed on machines these days, even brand new computers see benefits from running a windows registry repair utility frequently.Ideally, you want to run these registry cleaners often as you will be surrpised how quickly you can find your registry filling up with junk and slowing your computer down.
The best registry cleaners come with an automatic scheduling mode that will run like a virus checker, scanning and cleaning your registry at predefined intervals so your machine will always be running at peak performance.
Stop waiting around for your slow computer that may well be full of errors. Windows registry repair is a safe and simple procedure if you use only the best registry cleaners on the market.
Install one of the best registry cleaners for free now. Run it now, run it often, and your slow computer and expensive repair bills will be something you won't have to deal with again.
Cloud Backups are Secure Online Backups
We know your wondering why would you use the Internet as a backup method. Well, there are a great deal of reasons. First, if you back up your data on the Internet, you dont need any additional software or hardware. If you have Internet access, your good to go.Second, your data is available for you anywhere you can use the Internet from. And with proper encryption and security, nobody else will know it’s even out there.
The Internet provides a gateway to nearly unlimited amounts of data storage with quality provders that make online backup their business.I pay about $4/month for over 30 Gigs of data.Now I’m using 60% of my backup space which leaves plenty of room for my future updates at a very reasonable price.
The first step is to decide which service is best for you. Most sites that offer a free trial are more expensive on a monthly basis than those that don’t.So you can do a little homework and get a better deal by discovering and joining a site with great features and no hidden expenses.It will (in the end) save you a fair amount of money. With all the blogs, internet backup comparison sites, etc. it’s quite easy to make a good informed decision.
So now, you’ve decided which service provider you’ll use. Now you need to decide which files are crucial to you and that you need to backup. The online backup providers that give you software that does most of the work for you tend to be the best providers as well. and will upload the backup files only after encrypting them for security. As you can see what I described so far the best backup sites are very easy to use.And the best providers will run identically on the common operating systems (Windows, Linux, and OSX).
The reason is they want you to use their service and if it’s too difficult, customers will go someplace else. The market is highly competitive and services with lightweight features or only focused on Windows or MAC only, etc. generally arn’t very reliable and could not be there in a month or two. So make sure that they support Windows, Linux, and MacIntosh.They will if they’re a quality provider.
So, now that you have an overview of the concept of Internet backups, let’s review some questions for you to ask.
Do they have software that makes it easy?
Does their software provide all features on Linux OSX, and Windows?
Can you backup many computers with a single account?
What kind of Internet backup is it? How frequently can you back up?
Do they protect your files with encryption? You must insist on AES 256bit encryption to protect your data.
You have other issues that are important to you.But by doing a little research and answering these few questions will help you discern between “the men and the boys”.
