Posts Tagged ‘alternative to openfiler’

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In-the-Lab: Full ESX/vMotion Test Lab in a Box, Part 2

August 19, 2009

In Part 1 of this series we introduced the basic Lab-in-a-Box platform and outlined how it would be used to provide the three major components of a vMotion lab: (1) shared storage, (2) high speed network and (3) multiple ESX hosts. If you have followed along in your lab, you should now have an operating VMware ESXi 4 system with at least two drives and a properly configured network stack.

In Part 2 of this series we’re going to deploy a Virtual Storage Appliance (VSA) based on an open storage platform which uses Sun’s Zetabyte File System (ZFS) as its underpinnings. We’ve been working with Nexenta’s NexentaStor SAN operating system for some time now and will use it – with its web-based volume management – instead of deploying OpenSolaris and creating storage manually.

Part 2, Choosing a Virtual Storage Architecture

To get started on the VSA, we want to identify some key features and concepts that caused us to choose NexentaStor over a myriad of other options. These are:

  • NexentaStor is based on open storage concepts and licensing;
  • NexentaStor comes in a “free” developer’s version with 4TB 2TB of managed storage;
  • NexentaStor developer’s version includes snapshots, replication, CIFS, NFS and performance monitoring facilities;
  • NexentaStor is available in a fully supported, commercially licensed variant with very affordable $/TB licensing costs;
  • NexentaStor has proven extremely reliable and forgiving in the lab and in the field;
  • Nexenta is a VMware Technology Alliance Partner with VMware-specific plug-ins (commercial product) that facilitate the production use of NexentaStor with little administrative input;
  • Sun’s ZFS (and hence NexentaStor) was designed for commodity hardware and makes good use of additional RAM for cache as well as SSD’s for read and write caching;
  • Sun’s ZFS is designed to maximize end-to-end data integrity – a key point when ALL system components live in the storage domain (i.e. virtualized);
  • Sun’s ZFS employs several “simple but advanced” architectural concepts that maximize performance capabilities on commodity hardware: increasing IOPs and reducing latency;

While the performance features of NexentaStor/ZFS are well outside the capabilities of an inexpensive “all-in-one-box” lab, the concepts behind them are important enough to touch on briefly. Once understood, the concepts behind ZFS make it a compelling architecture to use with virtualized workloads. Eric Sproul has a short slide deck on ZFS that’s worth reviewing.

ZFS and Cache – DRAM, Disks and SSD’s

Legacy SAN architectures are typically split into two elements: cache and disks. While not always monolithic, the cache in legacy storage typically are single-purpose pools set aside to hold frequently accessed blocks of storage – allowing this information to be read/written from/to RAM instead of disk. Such caches are generally very expensive to expand (when possible) and may only accomodate one specific cache function (i.e. read or write, not both). Storage vendors employ many strategies to “predict” what information should stay in cache and how to manage it to effectively improve overall storage throughput.

New cache model used by ZFS allows main memory and fast SSDs to be used as read cache and write cache, reducing the need for large DRAM cache facilities.

New cache model used by ZFS allows main memory and fast SSDs to be used as read cache and write cache, reducing the need for large DRAM cache facilities.

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Nexenta Turns 2.0

June 30, 2009

Beth Pariseau, Senior News Writer for SearchStorage.com, has an interview with Nexenta CEO Evan Powell about the release of NexentaStor 2.0 today. The open source storage vendor is making some fundamentally “enterprise focused” changes to its platform in this release by adding active-active high availability features and 24/7 phone support.

“Version 2.0 is Nexenta’s attempt to “cross the chasm” between the open-source community and the traditional enterprise. Chief among these new features is the ability to perform fully automated two-way high availability between ZFS server nodes. Nexenta has already made synchronous replication and manual failover available for ZFS, which doesn’t offer those features natively, Powell said. With the release of Nexenta’s High Availability 1.0 software, failover and failback to the secondary server can happen without human intervention.”

SearchStorage.com

In a related webinar and conference call today, Powell reiterated Nexenta’s support of open storage saying, “we believe that you should own your storage. Legacy vendors want to lock you into their storage platform, but with Nexenta you can take your storage to any platform that speaks ZFS.” Powell sees Nexenta’s anti-lock-in approach as part of their wider value proposition. When asked about de-duplication technology, he referred to Sun’s prototyped de-duplication technology and the promise to introduce it into the main line this summer.

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