Take Five With Tom Fenton
Storage Problems and Proposed Solutions
Storage presents a lot of problems. It's expensive, it accumulates in all kinds of places where you can't find it, it's a hassle to move from point A to point B and it isn't always compatible from one vendor to the next. A lot of bright minds are working on a variety of virtualized storage schemes, but the pain points remain real. Here's a look at some difficulties and alleged remedies.
As Citrix notes, datacenter-based, dynamically provisioned desktops create a great deal of disk activity, which bogs down performance and greatly increases the use of expensive network storage. Some 80 percent of these writes to disk in environments with shared image desktops include temporary or non-persistent data that need not be saved in a storage-attached network (SAN) or network-attached storage (NAS) system. The Citrix answer to this dilemma is its new IntelliCache technology, which picks out this traffic and caches it to local, server-side disks, enhancing performance and slashing Virtual Desktop Infrastructure (VDI) costs. IntelliCache is included in the free version of XenServer, and will also be supported in a future release of reference architecture for XenDesktop 5.
F5 Networks is a big fan of virtualized storage, which it says removes a lot of complexity by creating a layer of abstraction that eliminates the links between users or apps and physical storage. However, a storage virtualization solution that only provides a virtualized storage layer isn't very effective. In order to really help IT contain increasing storage expenses, the solution must work across multiple OSes, storage platforms and file systems. In so doing, it must also offer an intelligent virtualized storage layer, so it can monitor client capacity, resource capacity and network conditions, as well as identify changes in real time. The final step, says F5, is facilitating and automating tasks such as storage tiering, which identifies the data's business value and matches it up with the right storage class.
Gluster tackles the problem of locating data in the data pool. The company says other storage vendors use a dedicated centralized metadata server to store all data-location information. This prevents metadata access from being parallelized and typically results in a bottleneck that reduces and prevents linear scalability. The metadata server is also a single point of failure that must be configured for high availability, because if it goes down, data cannot be accessed. Gluster bypasses these problems via a "no-metadata server" architecture that doesn't require an index of information to locate data in the data pool.
According to Virsto Software, without an effective storage strategy, the benefits of server virtualization can be offset by performance degradation, storage sprawl and increased complexity. Previously, the only way to deal with these issues was by over-provisioning storage. Virsto One, which installs in seconds on every Hyper-V physical server and integrates with the Hyper-V and Microsoft System Center solutions, manages I/O requests for each virtual machine (VM) on each physical host, dynamically and efficiently controlling how storage is allocated to each VM instance, as well as where it's placed on physical hard drives.
Asigra Cloud Backup is moving away from the use of agents with backup and recovery solutions, which typically require that agents installed on host servers be backed up by systems administrators. However, agent management can become extremely complex when the admin must work with different OSes and revision levels. Asigra doesn't require agents to be installed for each machine or app that needs to be protected. Instead, it reaches out over the network to back up OSes, file systems and applications, using industry programming interfaces.
Where do you think virtualized storage is lacking or improving? Tell me at [email protected].
Bruce Hoard is the new editor of Virtualization Review. Prior to taking this post, he was founding editor of Network World and spent 20 years as a freelance writer and editor in the IT industry.