The battle between storage and server virtualizationSpecial report: The battle between storage and server virtualization <<previous|next>> :The politics of VMware deployments
A new wrinkle: VMware over NFS
Jon Bock, senior product marketing manager for VMware, pointed out the work that VMware has done with NetApp to connect storage and server virtualization management through SnapManager software. NetApp's SnapManager for Virtual Infrastructures consists of a software agent that lets users manage NetApp snapshots within the VMware management console. But even as NetApp continues to increase support for VMware, the company is making strides of its own in the server virtualization market with organizations migrating VMware storage to industry-standard NFS to simplify management.
Users who combine VMware with NFS are still in the minority, but that minority is growing steadily. Companies such as AutoTrader have planned the switch from VMFS primarily because they're already used to working with NFS systems or want to consolidate management tasks.
Switching to NFS will allow AutoTrader to use NetApp's data protection features more efficiently as well as simplify management, according to AutoTrader Windows systems group manager Jason Cornell. "Both iSCSI [with VMFS] and NFS work fine, and the performance is about the same," he said. "It's a matter of supportability -- our admins understand supporting applications on NFS and have experience with that."
NetApp supports similar features such as SnapManager software integration for any kind of virtual host. When asked if they consider VMware a competitor, NetApp officials say only that the company is looking to support all virtual hosts equally.
Adds Wolf, "VMFS can be great, but it doesn't always have to be the major selling point." It can even be a weakness, he says, when users are trying to create transactionally consistent snapshots of data."You need to make sure that data has passed through the Hypervisor and memory if you want consistent snapshots," he said. "With a raw device, you don't have to worry about such things."
When it comes to using NFS instead of VMFS, the older file serving protocol already has had features developed for it that VMFS doesn't, such as thin provisioning, and backup via NDMP. On NetApp systems, features like snapshots, mirroring, replication and failover are also already built in.
Storage vendors can use ESX, too
While some storage vendors, particularly software-only storage vendors, look at VMware and see competition for management dominance over the data center, the parent company of VMware, EMC, was demonstrating ways it could use ESX to add value to its future storage systems at the recent EMC World conference in Las Vegas.
Within the company's "Innovation Showcase" exhibit, senior consulting software engineer Sorin Faibish was showing off a diagram of a project dubbed "Application-Aware Intelligent Storage." The prototype would combine artificial intelligence software capable of being "trained" with hardware-embedded VMware ESX servers to automatically spawn services such as data migration, encryption and replication to data as it comes into the cache on a storage array. The embedded ESX host would also run EMC's RecoverPoint CDP inside, logging and catalogging I/O, indexing data for input into a modeling engine, which would then decide on the proper way to store and protect the data before flushing it to disk.
Faibish's project would require development of advanced artificial intelligence software using concepts like neural networks, fuzzy-logic modeling and genetic-based learning. But, he added, tellingly, "It could prevent commoditization of the storage array."
Backup also a bone of contention
VMware provides virtual machine backup through the use of a proxy server, packaged under the name VMware Consolidated Backup (VCB). VCB allows backup tools to access data from virtual machines without requiring backup software agents on each virtual machine or physical host. This provides easier integration with existing backup tools, and gives users the ability to centrally manage virtual machine backups.
Despite recent updates to backup software products and VCB designed to simplify backing up virtual machines, backing up a virtual server environment remains a struggle for many users. Depending on their backup software tool, some users still face a choice between having an agent on every guest host or not getting granular backups. Other users can't decide whether to continue to use their existing backup software tools or go with VMware's VMFS snapshots.
As part of its effort to get the word out about its issues with some of VMware's approaches to storage, Symantec published the results of a survey of 100 users this spring which claim that storage management was one of the top challenges in VMware environments, and that doesn't just refer to primary storage for VMware hosts: Nearly half (45%) of the respondents said that backup and recovery was the biggest issue.
Despite all the updates to backup software products and VMware's ESX server over the last year, designed to make backing up virtual machines easier, users at the Storage Decisions 2007 conference in New York said that backup in a virtual server environment remains a struggle.
Tom Trist, IT supervisor for Harris Corp., said he's unsure if it's better to use his EMC Legato Networker backup software to back up virtual machines or perform snapshots through VMware's virtual machine file system (VMFS).
Neither option is ideal for Trist. "Using our existing backup software would require an agent on each guest host, which taxes the resources on the physical hosts but would also give us file-level restore, which a snapshot wouldn't," he said.
Backup vendors continue to update products with new features for VMware, such as the granular recovery for VMware hosts that Symantec came out with for NetBackup version 6.5.2 and higher at this year's Symantec Vision conference. The recovery feature permits object-level restores from VMware backups without requiring the data to be backed up twice. However, Symantec remains the only major backup vendor on the market to offer such a feature.
03 Jul 2008