A very common misperception is that iSCSI SANs are not as secure as Fibre Channel SANs. In fact, when logically or physically separated, iSCSI networks are just as secure as Fibre Channel.
iSCSI is sending SCSI commands in IP packets. To be more specific, iSCSI is designed to be a protocol for a storage initiator (usually a server) to send SCSI commands to a storage target (usually a tape or disk) over IP. iSCSI technology provides compelling price/performance in a simplified architecture while improving manageability in virtualized environments.
SCSI protocol is not designed to handle lost frames, or blocks. It expects them to arrive, no matter if they’re damaged (have CRC errors). IP or Ethernet will not deliver a frame which has CRC errors; behavior which is not compatible with what SCSI expects. This is why iSCSI uses TCP.
The way to improve performance of iSCSI is to use HBAs (Ethernet NIC) with TCP offload, which do all the necessary calculations on an embedded ASIC, significantly reducing the processing latency. Majority of storage arrays with iSCSI already make use of TCP offload, so some of the performance problems that you’re seeing are quite likely caused by a poor choice of Ethernet NIC in the server (or incorrect/badly configured NIC drivers). Broadcom NetXtreme II network adapters can be used for Iscsi Offload.
Specifically, iSCSI offers virtualized environments simplified deployment, comprehensive storage management and data protection functionality, and seamless VM mobility. Dell iSCSI solutions give customers the “Storage Direct” advantage – the ability to seamlessly integrate virtualization into an overall, optimized storage environment.
In Linux you can use iscsiadm command to login the ISCSI targets and allows to discover.In CentOS 5.1 adds over the 5.0 version is an updated iscsi-initiator-utils. It adds the “iface” context, which allows you to configure more than one physical interface for connection to iSCSI targets. With CentOS 5.0 the best alternative for redundant paths was to use the Linux bonding driver and create an active-standby bond between two interfaces. This is great for redundancy, but doesn’t provide and load balancing.
Dell’s PS Series group provides iSCSI-accessible block storage. With the latest version of the PS Series firmware and the addition of an EqualLogic FS7500, the same PS Series group can provide block storage and support for NAS (Network Attached Storage). FS7500 is integrated directly into the EqualLogic Group Manager to improve productivity, making it easy to configure and manage iSCSI, CIFS and NFS storage.
Eddison Sherry had been working in Linux and Storage solutions for long years. He had been writing blogs and article on the Linux Storage , Linux Commands
and Linux Server Administration. If you are working on Linux or Unix Server its best to have a look on his blogs at Linux Technical Forum
Blow Your Competition Out Of The Water With These Search Engine Optimization Tricks
By increasing traffic to a blog or website, there is a good possibility that there will be a resulting increase in the sales from that source from the additional visitors. Optimizing your search engine will help to make the web site you have made more accessible. In this article you will find great advice for maximizing your optimization efforts.
You should make sure that the search engine optimization you choose, uses a quality and proven technique. Stuffing keywords haphazardly throughout your site won't do anything but lower your audience's confidence in your legitimacy. Consider custom-made content that is specific to your business. This will draw in the audience and encourage them to explore the rest of your website.
When you try to increase search engine optimization, you should make your URL something easy and understandable. It should be clear what your site is about. That way, people will known what they are clicking on when they are looking for something using a search engine and they will more likely click on your site.
In order to help crawlers and spiders index your web site, you should create a site map. A site map is a list of all the pages that make up your site. By creating one, web spiders will be able to discover even the most obscure and hidden pages, as well as to receive other important information. This will increase your visibility on the internet.
If video or audio items are shown on your website, you should have transcripts of these included. The transcripts allow your content to be easily understood by search engine robots. This will ensure your website gets a higher ranking.
Keep your content fresh. While having lots of content is important, it has to be up to date. A search engine will track how frequently your site is updated and this has an effect on your rank in the freshness category. Any form of change, whether it's a news article or a blog post, will help to boost your rank.
As much as possible, stay away from frames in your website. Search engines can't index framed pages. The best that they will be able to do is to index your home page. This means that, if the majority of your site uses frames, then the majority of your site will not be indexed.
If you want to avoid a three to six month period of your site being in a ranking abyss, do not make a lot of link exchanges or buy a lot of links right away. Take your time marketing your site slowly to the internet and your rank will go up much quicker.
If you have embedded videos on your web site, be sure to include them in your sitemap. Doing so lets the search engines know that your video content is actually part of your web site. This will help bring more traffic to your site, since viewers will be more likely to come to your site to watch your video rather than going to an external hosting site.
When search results are shown, it's probably the results showing on the first two pages that will see the highest traffic. The ideas you've read here will help you to build traffic and increase the profits you receive from your website or blog. Optimizing your site or blog can do a lot for your business.