Author Archive

Turning from Metadata performance to throughput performance, we examines the impact of journal size on ext4 when the journal is disk-based. Dig into the numbers and see what you can do to improve throughput performance.

The past couple of weeks we ran the numbers on metadata performance for ramdisks and hard drive-based journals for ext4. Now let’s compare/contrast the two journal devices and see what trends emerge.

Previously, we examined the impact of journal size using a separate disk on metadata performance as measured by fdtree. In this follow-up we repeat the same test but use a ramdisk for the journal, thereby boosting the best performance. Or does it?

Recently we saw that the journal device location, unfortunately, didn’t make much of a difference on ext4 metadata performance. But can the size of the journal will have an impact on metadata performance? The first in a series of articles examining the journal size and performance.

In the quest for more performance there are two new standards for SATA and SAS focused on doubling current throughput to 6 Gbps. While the standards may sound like a nice potential boost don’t expect individual hard drives to increase in performance.

In the never-ending quest for more performance, we examine three different journaling device options for ext4 with an eye toward improving metadata performance. Who doesn’t like speed?

It’s the end of the year and that means it’s time to either make predictions for the coming year or review the highlights from the past year. This article takes a look at the cool things that happened around storage in the past year and perhaps hints at some things in the coming year.

Everyone loves a shiny new kernel. The latest one, 2.6.32, was released on Dec. 3 and there are some nice updates/fixes for file systems and IO in general. But there is a very important change for the CFQ IO scheduler that you need to understand.

The SuperComputing Conference/Exhibition is always a great conference for learning about storage trends in the HPC world. This year the alert attendee could spot two emerging trends: smaller companies developing innovative storage solutions and the rise of flash storage units.

Cloud Storage — while perhaps not the best label ever invented — holds promise for the massive future storage requirements looming on the horizon. And does it at a very good price/performance ratio. This article takes a quick look at the concepts and the challenges of Cloud Storage.

iSCSI is one of the hottest topics in Storage because it allows you to create centralized SANs using TCP networks rather than Fibre Channel (FC) networks. Get a handle on the main iSCSI concepts and terminology.

The last article talked about the anatomy of SSDs and the origins of some of the their characteristics. In this article, we break down tuning storage and file systems for SSDs with an eye toward improving performance and helping overcome some of the platform’s limitations.

SSDs (Solid-State Drives) are a hot topic right now for a number of reasons; not the least of which being their power to performance ratio. But to better understand SSDs you should first get a grip on how they are constructed and the features/limitations of these drives.

A fairly common Linux storage question: Which is better for data striping, RAID-0 or LVM? Let’s take a look at these two tools and see how they perform data striping tasks.

The last article was a quick overview of the 4 schedulers in the Linux kernel. This article takes a closer look at the Completely Fair Queuing (CFQ) scheduler and how you can tune it.

The Linux kernel has several different IO schedulers. This article provides an introduction to the concept of schedulers and what options exist for Linux.

We finish off our IOzone performance exploration of the major Linux file systems. This time adding ext2, jfs, xfs, btrfs, and reiserfs. Let’s take a look at the numbers.

One of the hottest topics in the enterprise storage world is deduplication. We take a look at the technology behind the concept and discuss where it is best applicable in your storage strategy.

While metadata performance is important, another critical metric for measuring file systems is throughput. We put three Linux file systems their paces with IOzone.

More performance: We add five file systems to our previous benchmark results to creating a “uber” article on metadata file system performance. We follow the “good” benchmarking guidelines presented in a previous article and examine the good, the bad and the interesting.

Using the principles of good benchmarking, we explore the metadata performance of four linux file systems using a simple benchmark, fdtree.

Backups are a technology or process that everyone — everyone! — needs to consider. This article looks at some on-line backup options for Linux that can apply to the spectrum of home to enterprise-class users.

Linux comes with software-based RAID that can be used to provide either a performance boost or add a degree of data protection. This article gives a quick introduction to Linux software RAID and walks through how to create a simple RAID-1 array.

Benchmarking has become synonymous with marketeering to the point it is almost useless. This article takes a look at a very important paper that can demonstrate how bad it has become and makes recommendations on how to improve the situation.

Logical Volume Management (LVM) on Linux: A great tool for creating pools of storage hardware that can be divided, resized, or used for snapshots.

Protecting your data has become more important than ever. Let’s look at some options for encrypting Linux file systems.

Diving deeper into UnionFS: walking through how to create and manage large file systems using the principles of ChunkFS and UnionFS.

Jeff Layton talks to Valerie Aurora, file system developer and open source evangelist, about a wide range of subjects including her background in file systems, ChunkFS, the Union file system and how the developer ecosystem can chip in.

Need to have write capability on your SquashFS compressed filesystem? UnionFS to the rescue!

There is a new file distributed file system in the staging area of the 2.6.30 kernel called POHMELFS. Sporting better performance than classic NFS, it’s definitely worth a look.

Ramdisks can offer a level of performance that is simply amazing. More than just a tool for benchmarking, there are new devices that utilize ramdisks for a bit of the ultra-performance.

FS-Cache along with CacheFS is now in the 2.6.30 kernel and can be used for local caching of AFS and NFS.

Who knew that compression could be so useful in file systems? SquashFS, typically used for embedded systems, can be a great fit for laptops, desktops and, yes, even servers.

The 2.6.30 kernel is chock full of next-gen file systems. One such example is NILFS, a new log-structured file system that dramatically improves write performance.

Need details on your file system’s data? FS_scan allows you dig deep into your storage, giving you the ability to perform trend analysis on the results.

The vast of amount of data being stored in this day and age, naturally leads to files sitting unused for longer and longer periods of time. A new app, agedu, can quickly tell you what data on your filesystem is lying fallow.

The founder of btrfs talks about features, terabyte raid arrays and comparisons with ZFS.

ZFS may be locked into the Solaris operating system but “Butter FS” is on the horizon and it’s boasting more features and better performance.

Jeff Layton talks with Theodore Ts’o about getting the best performance out of your file system, painless migration and the work still to do.

Destined to become the default file system for the more popular Linux distributions, ext4 is out of experimental mode and gearing up for production environments. Here’s what you need to know.

Silence the struggle around cluster software stack configuration. Caos NSA is a distribution that focuses on making things simple, easy to install and upgrade, and easy to manage.

NFS frees you from proprietary file systems and, coupled with Infiniband, is the only standard file system that can be used for high-peroformance distributed processing.

While strace is often used for troubleshooting and debugging, you can also use strace to get started on examining the I/O pattern of your serial codes.

In the last installment of our Parallel Platters series, Jeff Layton looks at the next generation of parallel file systems: Object Based File Systems.

Getting the most out of your cluster is always important. But how exactly is that done? Do you really need to dissect your code and analyze every instruction to get optimal performance? Do you need to build custom kernels? Not necessarily. By testing some basic assumptions, you may be able to eke ten-node performance out of an eight-node cluster. Here’s how.