I suspect that a decent percentage of folks reading this will be attending SNW in Orlando next week. But those folks may not be tracking lovable Wilma, the record setting category 5 hurricane that’s bearing down on the state this weekend. …

Unsure about what RAID level works best for what situation.. read on.

Considering using Replication to move or backup data from remote locations? - some practical advice for sizing the task

There are other posts from my fellow Storage Advisors that go into the gory details of RAID, its importance, and the varying levels of RAID available to customers today. This post is far less technical than that and more literal. To that I ask: When is RAID not RAID?

Let’s first start out by examining the acronym “RAID”. Since RAID stands for “Redundant Array of Independent Disks” you’d think that all RAID levels are “Redundant”, right? Wrong! RAID level 0 (zero) has no redundancy at all. In fact RAID 0, although having the RAID characteristic of stripping data across all disks, does not maintain any redundancy or parity of data…

First, it’s probably worth a quick definition of what snapshots are for those that thought I was talking about some tawdry pictures.

A definition offered by SNIA (Storage Networking Industry Association http://www.snia.org/) says,”A fully usable copy of a defined collection of data that contains an image of the data as it appeared at the point in time at which the copy was initiated. A snapshot may be either a duplicate or a replicate of the data it represents.” In practical terms snapshots are a point-in-time copy of a dataset. In some cases it may be a read only copy and in others it may be completely writable. Generally, it is a way to have a local backup copy of data that doesn’t take up double the amount of space. More on how snapshots work and their inherent benefits another time though…

So much of what the storage industry focuses on is around the high dollar, high end, and high touch enterprises. While certainly the most sophisticated in their infrastructures they are also the most “beefed up” with expertise and staff to handle these very complex environments.

Now what about the rest of the world? What about the small doctors offices, law offices, graphics design companies, consultancy firms, retail stores and everything else in between? There is lots of data being generated and the need for a reliable storage infrastructure is just as important to the small business owner as it is for the largest of enterprises. The point I’m trying to make is that it’s all relative. Generally, storage and the protection of the data on it is very important…

I have asked many IT mangers this question: “What is the rate of change of your companies data” Most cannot answer this question. Surprisingly, some big companies with larger IT shops don’t even know this, but it isn’t really on the minds of the small business with limited IT staff.

Why is this number so important? First off, if you are considering implementing any kind of ILM (Information Lifecycle Management) program, you will need to know this. Mainly, the rate of change of your data tells you how much storage you are currently using and how and where it is growing. If you are considering using a remote backup strategy for your remote offices, and want to replicate the data back to a central spot, your rate of change of data is critical. If you have a lot of data, and the data changes too frequently you might not have the CPU cycles to process or the network bandwidth to transfer all of that data. Even with a replication program that transfers ONLY differential byte-level data. More on this in another blog I am working on…

So, what will this column be about, from my perspective? We were anointed, “Storage Advisors, because it is about giving Advice, hopefully useful advice. We “Advisors” find it hard enough to wade through the Morass of Storage terms, technologies, and solutions on a daily basis. I truly feel for the average small to medium business that have been left to fend for themselves trying to figure out their storage needs and what would be best for them. This is where we might be able to help.

Storage technology has been around since the conception of computers. Some IT managers have even referred to Storage as a “necessary evil-” sometimes mis-understood, difficult, and expensive. SCSI and FibreChannel have definitely earned this reputation…

I remember when all you had to do was choose which tape drive or library you were going to use to backup your data. Media capacity and speed had to be considered – and, of course your budget. Now with all the options for disk-based backup; snapshots, replication and mirroring techniques, Virtual Tape Libraries (VTL), and the latest three letter acronym in storage (CDP – Continuous Data Protection), does that old archaic tape technology still have a place? I think so… doesn’t it?

Let’s dig a little deeper. With disk-based backup techniques you can replicate data asynchronously on a scheduled basis; you can mirror data real-time; you can migrate older data to lower cost storage based on policies; or you can simply make the disk look just like a tape. There are even some products out there that let you remove disk drives after backup just like tape media for offsite storage…

There’s lots of information on the new Serial Attached SCSI (SAS) standard just coming online - but one of the questions that keeps coming to mind for me has little to do with the technical merits of SAS but instead what is the best host interconnect with all the different options that now exist.

There’s hardly an argument that SAS as a drive interconnect isn’t the next logical step and the best replacement for the aging parallel SCSI. With SATA and FC drives capping the low-end and high-end drive markets respectively - SAS surely has a home in the middle. Internal host connections are pretty straight forward - Internal host drives plug into their respective drive interconnects: FC to FC, SATA to SATA and SAS to SAS. (We won’t talk about the compatibility of SATA II and SAS in this post - but that’s certainly a cool feature…)