Datacenter

Extended File Attributes Rock!
Worldwide, data is growing at a tremendous rate. However, one recent study has pointed out that the size of files is not necessarily growing at the same rate; meaning the number of files is growing rapidly. How do we manage all of this data and files? While the answer to that question is complex, one place we can start is with Extended File Attributes.
Checksumming Files to Find Bit-Rot
In a previous article extended file attributes were presented. These are additional bits of metadata that are tied to the file and can be used in a variety of ways. One of these ways is to add checksums to the file so that corrupted data can be detected. Let's take a look at how we can do this including some simple Python examples.
What’s an inode?
As you might have noticed, we love talking about file systems. In these discussions the term "inode" is often thrown about. But what is an inode and how does it relate to a file system? Glad you asked.
SandForce 1222 SSD Testing, Part 5: Detailed Throughput and IOPS Analysis with a 2.6.38.2 Kernel
In this series we've been working over the 2.6.32 kernel, which is a bit old. Let's kick the tires on a 2.6.38.2 kernel to see if it helps or hurts performance of the SandForce SSD.
iotop: Per Process I/O Usage
Based on a reader comment, we take iotop for a spin to see if it can be used for monitoring the IO usage of individual processes on a system. The result? It has some interesting capability that we haven't found in other tools.
SandForce 1222 SSD Testing, Part 4: Detailed IOPS Analysis
In this installment of our series examining the performance of SandForce-based consumer SSDs we dig into the IOPS performance of the drive. How does it stand up to an enterprise-class SSD? Let's find out.
SandForce 1222 SSD Testing, Part 3: Detailed Throughput Analysis
Our last two articles have presented an initial performance examination of a consumer SandForce based SSD from a throughput and IOPS perspective. In this article we dive deeper into the throughput performance of the drive, along with a comparison to an Intel X-25E SSD. I think you will be surprised at what is discovered.
SandForce 1222 SSD Testing – Part 2: Initial IOPS Results
SandForce has developed a very interesting and unique SSD controller that uses real-time data compression. This affects data throughput and SSD longevity. In this article, we perform an initial examination of the IOPS performance of a SandForce 1222-based SSD. The results can be pretty amazing.
SandForce 1222 SSD Testing, Part 1: Initial Throughput Results
SandForce has developed a very interesting and unique SSD controller that uses real-time data compression. This can improve performance (throughput) and extend the life of the SSD but it hinges upon the compressibility of your data. This article is the first part in a series that examines the performance of a SandForce 1222-based SSD and the impact of data compressibility.
Software RAID on Linux with mdadm
Now that we've completed our initial examination of the basics of RAID levels (including Nested RAID) it's time to turn our attention to RAID functionality on Linux using software. In this article we will be discussing mdadm -- the software RAID administration tool for Linux. It comes with virtually every Linux distribution and has some unique features that many hardware RAID cards don't.
Aligning SSD Partitions
Do you have a brand new SSD? Do you plan to partition it? Let's talk about the best way to set up your SSD so partitions -- and the resulting file systems -- align on page boundaries, thus improving performance and minimizing the number of rewrite cycles.
Nested-RAID: The Triple Lindy
Thus far we have talked about single-level RAID configurations and Nested RAID configurations. But we've artificially restricted ourselves to only two levels in Nested RAID. Couldn't we have three RAID levels or more? The answer is yes, and in this article we'll talk about three levels (the proverbial "Triple Lindy") and have some fun with a couple of examples.
Tools for Storage Monitoring: nfsiostat
In our never ending-quest for reasonable storage management and monitoring tools, we examine a simple tool in the sysstat collection: nfsiostat. Coupled with iostat, the combination creates a nice set of tools for monitoring NFS.
On-the-fly Data Compression for SSDs
The key to good SSD performance is the controller. One SSD controller that has received good reviews is the SandForce SF-1200. However, a recent test of a SF-1200 SSD reveals some interesting things about what this controller does and just how it does it. Depending upon your point of view and, radically, your data, performance can be amazing.
3TB Drives are Here
In real estate it's about location. In storage it's about capacity. The next crop of high density drives are available but there are some gotchas related to some 3TB drives that you need to know before making a land grab.
Short Stroking Hard Disks for Performance
Less is more. More performance, that is. Learn how to use less of your hard drive (even though you paid for all of it) to get an I/O boost.
Linux 2.6.37: Scalability Improvements Abound
While 2.6.37 might be considered a quiet release, there are some very nice scalability improvements for file systems and one cool new feature that warrant a review.
Nested-RAID: RAID-5 and RAID-6 Based Configurations
A Nested RAID configuration is built on top of a standard single-level RAID configuration in order to address performance and data redundancy limitations. Digging deeper into Nested RAID, we check out RAID-5 and RAID-6, which have some truly amazing features (if you have enough drives).
Intro to Nested-RAID: RAID-01 and RAID-10
In the last article we reviewed the most basic RAID levels. In this article, we take things to the next level and discuss what is called "Nested RAID Levels". These concepts can provide both performance and redundancy for a data-rich world. We then look at RAID-01 and RAID-10; two of the most common Nested RAID configurations.
Introduction to RAID
RAID is one of those technologies that has really revolutionized storage. In this article, we'll review the six most common single RAID levels and describe how each works and what issues surround them.