When EMC Corp. rolled out its VNX and VNXestorage platform this year, it shone a bright light on unified storage systems and intensified its competition with NetApp.
NetApp and EMC aren’t the only vendors to offer unified storage -- most major vendors have systems that support multiple protocols -- but NetApp’s FAS and EMC’s VNX are the most talked about. They're also the most scrutinized and serve as the models that most people refer to when they discuss what is and isn’t true about unified storage platforms.
Unified storage systems allow one-box access to both block and file storage, typically over Fibre Channel (FC) or Ethernet networks. NetApp first offered multiprotocol storage in 2002 when it added SAN or block capability to its NAS filer platform. All NetApp FAS systems from entry level to enterprise support file storage via CIFS and NFS and block storage over Fibre Channel and iSCSI.
EMC merged its midrange Clariion SAN and Celerra NAS platforms into the VNX. EMC has a separate enterprise SAN Symmetrix family but the VNX put the two largest pure-play storage system vendors into a head-to-head battle with systems that cover most of the overall data storage market.
Let’s take a look under the hood to see how the NetApp and EMC unified storage products compare.
NetApp FAS series
NetApp’s FAS scales from the FAS2020 with 68 disk drives to the FAS6280 with 1,440 drives. Each system comes with NetApp’s Data Ontap 8.0 operating system (OS) that includes all NetApp’s advanced data services, including compression, data deduplication, disaster recovery and snapshot capabilities.
The FAS2000 series includes the 2U 2020, the 2U 2040 and the 4U 2050 targeted at mid-sized companies, remote and branch offices, and large enterprise departments. The series’ maximum supported drives range from 68 to 136 SAS, FC or SATA drives, and includes two PCI Express (PCIe) expansion slots.
NetApp’s FAS3100 series are all 6U chassis with eight PCIe expansion slots and 64-bit controller architectures. They're targeted at enterprise applications and technical computing. The 3100 line supports between 420 and 840 SAS, FC and SATA drives.
The FAS3200 product line features a wide range of speeds and feeds. Each 3200 product includes four PCIe expansion slots; in addition, the 3240 and 3270 can add eight more PCIe expansion slots for greater I/O capabilities. Without the additional expansion slots, each unit is a 3U form-factor and supports from 240 to 960 drives.
NetApp’s largest FAS product line is the 6200 for large enterprises. The 6210 is a single 6U unit with two controllers, 48 GB of RAM, a 3 TB Flash Cache, eight 10 Gigabit Ethernet (GbE) connectors and eight PCIe expansion slots. It holds up to 1,200 drives. The 6240 and 6280 are each dual-enclosure 12U units, hold up to 1,440 drives and include eight 10 GbE connectors and 24 PCIe expansion slots. The 6240 comes with 96 GB of RAM and 6 TB Flash Cache. The 6280 has 192 GB of RAM and an 8 TB Flash Cache.
NetApp also has its V-Series, which virtualizes storage from other vendors, including EMC, to add file capability.
EMC VNX
The EMC VNX product line comes in three flavors: VNXe for small- and medium-sized businesses (SMBs), VNX for mid-sized organizations and enterprises, and the VNX Series Gateway (VG) that provide NAS capability for EMC SANs. All the products in the VNXe, VNX and VG product lines use EMC’s Unisphere unified management software.
Both the VNXe3100 and VNXe3300 include up to two block-storage processors, file deduplication, compression, thin provisioning, and snapshots. The 2U VNXe3100 holds from six to a maximum of 96 SAS or Nearline-SAS (NL-SAS) drives. The 3U VNXe3300 includes up to 120 SAS or NL-SAS drives.
All the VNX series products support Flash, SAS and NL-SAS drives, as well as two block storage processors, virtual provisioning and EMC’s SAN Copy data copying technology. The VNX5100 includes up to 75 drives, the VNX5300 holds up to 125 drives and the VNX5500 holds up to 250 drives; the VNX5700 holds up to 500 drives, while the VNX7500 holds up to 1,000 drives.
The VNX Series Gateway provide file access to existing VNX, Symmetrix and Clariion storage systems. Both the VNX VG2 and VG8 support file deduplication and compression, virtual provisioning and EMC’s SnapSure snapshot technology. The VNX VG2 supports up to two X-blades and 256 TB of total usable capacity. The VG8 supports up to eight X-blades and 1.8 PB of usable capacity.
While NetApp’s FAS systems run DataOntap, VNX runs the Clariion Flare and Celerra DART operating systems although EMC hasn't spelled out exactly how the two OSes co-exist in one box.
Commonalities include single-pane-of-glass management
NetApp and EMC also provide single-pane-of-glass storage management for their unified solutions. Analysts say a single management interface is one of the main attributes that makes a true unified system.
“Whenever people talk about multiprotocol, the first things they think about is management overhead and consistency of utilization across the protocols,” said Ashish Nadkarni, a senior analyst and consultant at Taneja Group. “Am I going to be sitting around with five interfaces all utilizing different physical components of the same system?”
EMC’s Unisphere supports the VNXe and VNX product lines, as well as EMC’s Clariion, Celerra products and RecoverPoint/SE replication product. Unisphere’s single sign-on web interface works in both physical and virtual environments and plugs into an existing environment without modification.
NetApp’s OnCommand management software includes System Manager for single storage systems and Operations Manager for multiple NetApp systems. OnCommand controls, automates and analyzes storage infrastructure. NetApp also provides Virtual Storage Console (VSC) plug-ins for managing FAS systems within VMware Inc.’s vCenter management platform.
“We’re not hell bent on having administrators come to our console to manage storage,” said Chris Cummings, NetApp’s vice president of product and solutions marketing.
When EMC launched the VNX family, NetApp executives said it wasn’t a true unified storage platform because it runs the Celerra and Clariion software stacks separately on the Intel Corp. Xeon quad-core processors. But Taneja Group's Nadkarni said that‘s not much of an issue for customers. “NetApp started from a single code basis and branched out into other areas,” he said.“EMC is now started from the other side and is coming to a converged solution. From a customer’s prospective, it’s not that relevant anymore.”
Different philosophies on storage tiering
EMC and NetApp also take a different approach to storage tiering across their product lines.
EMC leverages solid-state drives (SSDs) and Fully Automated Storage Tiering (FAST) software for automated tiering while NetApp creates what it calls a virtual storage layer.
FAST is policy-based, application-aware software that moves data between SSDs, Fibre Channel and SATA drives. It moves frequently used data to higher-performing drives, such as SSDs and FC drives, according to user-defined policies. FAST can run automated or in user-approval mode; it works at the sub-LUN level by moving volumes across disks.
“Automated tiering is a key capability to allow customers to not only dynamically meet their performance needs but to do so in a cost-effective manner,” said Jon Siegal, director of product marketing for EMC’s unified storage division.
While EMC’s approach to tiering is the traditional one taken by storage vendors, NetApp approaches it differently. NetApp’s virtual storage tiering does not use tiering software as EMC and others do. NetApp has a Flash Cache PCIe-based solid-state storage device that speeds performance on specific applications, such as data warehousing. It also supports SSDs in the array as other storage vendors do, but recommends that only for customers who need all reads and writes to be fast instead of peak performance on specific applications.
NetApp’s Cummings said Flash Cache identifies hot data at the block level in real-time and uses the virtual storage tier to move additional resources to support that data. He said that avoids having to move data around, which could create potential backup and file deletion problems.
“We look at this virtual storage tier and say it’s simpler, cheaper and you don’t run into these types of problems,” Cummings said.
Clustering unified storage
Unified storage systems haven't been known for their clustering and high-availability capabilities. NetApp allows you to cluster your multiprotocol system in pairs using a global namespace at implementation for business continuity, performance needs and load balancing, while the VNX series can run in a two-node mode.
The NetApp clusters can be separated geographically depending on your networking capabilities. During implementation you indicate whether you want to scale up your system or scale it out with clusters. Then you define your clusters. “So you can scale it up or scale it out,” Cummings said.“Running scale out in a unified [system] is going to add a bunch more value to customers.”
The VNX series can run with two nodes for mirroring. EMC’s Siegal said the VNX family is built as a scale-up architecture for now, and pointed customers to EMC’s recent Isilon Systems Inc. acquisition for a scale-out model.
While EMC’s and NetApp’s code base and auto-tiering technologies are markedly different, neither has been proven to be better than the other.
“Don’t worry about splitting those hairs,” said Greg Schulz, founder and senior analyst at StorageIO Group. “Focus on your needs when choosing a multiprotocol system. How is the performance? How is it managed? How’s the availability?” He advises people considering the systems to compare the technology differences to their specific needs to decide which way to go.
07 Jul 2011