Inside System Storage -- by Tony PearsonTony Pearson is a Master Inventor and Senior IT Specialist for the IBM System Storage product line at the IBM Executive Briefing Center in Tucson Arizona, and featured contributor to IBM's developerWorks. In 2011, Tony celebrated his 25th year anniversary with IBM Storage on the same day as the IBM's Centennial. He is author of the Inside System Storage series of books. This blog is for the open exchange of ideas relating to storage and storage networking hardware, software and services. You can also follow him on Twitter @az990tony.
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Our industry is full of acronyms, and sometimes spelling out what words an acronym stands for is not enough to explain it fully.
It reminds me of an old story within IBM. A customer engineer (or "CE" for short) was repairing an air-cooled server, and found the failing part being a "FAN". Not knowing what this stood for, he looked up the acronym in the offical "IBM list of acronyms" and found that it stood for "Forced Air Network". Apparently, so many people did not realize that a FAN was just a "fan" that they needed to add an entry to remind people what this little motorized propeller was for.
This brings me to Tony Asaro's Fun with FAN blog entry which mentions yet another definition for FAN, that of "File Area Network". The concept is not new, but some developments this year help make it more a reality.
To join the rest of the world, new types of data set were created for the z/OS operating system, known as HFS and zFS. These held file systems in the sense we know them today, comparable in hierarchical organization of files on Windows, Linux and UNIX platforms. These could be linked and mounted together in larger hierarchical structures across the sysplex.
The concept of files and file systems is a fairly new concept. Prior to this, applications read and wrote directly in terms of blocks, typically fixed length multiples of 512 bytes. For a while, database management systems offered a choice, direct block access or file level access. The former may have offered slightly better performance, but the latter was easier to administer. Without file system, specialized tools were often required to diagnose and fix problems on block-oriented "raw logical" volumes.
This launched a "my file system is better than yours" war which continues today. The official standard is POSIX, but every file system tries to give some proprietary advantage by offering unique features. Sun's file system offers support for "sparse" files, which is ideal for certain mathematical processing of tables. Microsoft's NTFS offers biult-in compression, designed for the laptop user. IBM's JFS2 and Linux's EXT3 file systems support journaling, which tracks updates to file system structures in a separate journal to minimize data corruption in the event of a power outage, and thus speed up the re-boot process. Anyone who has ever waited for a "Scan Disk" or "fsck" process to finish knows what I'm talking about. Of course, if an application deviates from POSIX standards, and exploits some unique feature of a file system, it then limits its portability and market appeal.
The two competing NAS file systems are also different. Common Internet File System (CIFS) was developed initially by IBM and Microsoft to provide interoperability between DOS, Windows and OS/2. Meanwhile, Network File System (NFS) was the darling of nearly every UNIX and Linux distribution, and even has clients on operating platforms as diverse as MacOS, i5/OS, and z/OS. Today, nearly every platform supports one or both of these standards.
Bottom line, file systems are here to stay. Any slight advantages to use raw logical volumes for databases and applications are losing out to the robust set of file system utilities that can be used across a broad set of platforms and applications.Read More]
For those of you worried about my mysterious absence on the blogosphere, I am getting better. Sorry for not posting much lately, I have had more serious issues to worry about. I am awaiting results on whether I have Dengue fever from Brazil, Avian flu from Thailand, Malaria from Kenya, or perhaps it is just food poisoning from the otherwise fabulous French cuisine I ate last week in the South Pacific. Well, I am back in town for a while, and hopefully will recover to full health, and have some time to reflect my thoughts on storage topics.
Speaking of which, a lot has happened while I was out. Let's take a quick look.
IBM has bundled our midrange DS4000 disk with SAN networking switch in a convenient 42U-high rack, and nicknamed thisSAN-in-a-can.
In SearchDataCenter.com, Matt Stanberry's article Sun rolls out data center Winnebago indicates Sun has taken IBM's SAN-in-a-can concept to the next level.
This is an interesting development. To understand it better, we need to go back to the 1930s. Malcolm McLean invented the shipping container in the 1930s in New Jersey, and later founded Sea-Land corporation. Rather than unpacking products from a ship, load onto a truck, then move those products onto a train, his innovation was to create a container that could be packed full of products, carried from ship, to truck, to train, without loading and unloading individual products as transportation means change. He named the size of his container "TEU".
TEU = 20 ft x 8.5 ft x 8.5 ft
In 1966, the standard shape and size was adopted by International Organization for Standardization (ISO).Today, over 90% of freight containers are 1 or 2 TEU
Sun's announcement is that they have packed up to 240 UNIX servers into a single TEU container. This can be dropped off at your facility, hook up your power and cooling, and start running. An alternative version is a disk-farm-in-a-can, having the TEU container filled with up to 2 PB of disk storage capacity.Read More]
Here we are again at Top Gun class.In between class topics, we often show short video clips.
This week, we saw IBM Executive Bob Hoey's wisdom on selling mainframe computers. Bob is the VP of Sales for our System z server line, but the lessons might also apply to high-end disk or enterprise tape libraries.Read More]