NetApp says there will be a 2-tier storage array in future, with hot data in flash and bulk data held on SATA Drives. Startup Nimble Storage says it's here now with its CS-Series, which combines the attributes of separate EqualLogic and Data Domain arrays in one box.
The company has been started up by people who used to work at Data Domain and NetApp. They say the hottest storage products now are iSCSI arrays like those from Dell EqualLogic and HP Left Hand, the P4000 range, on the one hand, and deduplicating disk backup products from EMC Data Domain. Their concept is to combine the two, do away with separate iSCSI SAN storage and disk backup arrays, by having deduplicated snapshot data held on SATA drives in the iSCSI array.
This is enhanced by then getting rid of high-performance SAS drives in the iSCSI box and replacing them with a combination of Flash cache and additional SATA drives. Multi-level cell Intel flash is used for the cache. The ratio of flash to primary disk storage is about 1:10, and is based on analysis of access patterns.
Active data gets copied to cache much faster than tiering software, such as that used by Compellent, can detect hot data blocks and move them from disk drives to flash solid state drives.
The Nimble Storage CS-Series products use inline compression on the primary data held on SATA dives and the copies in the cache. Marketing VP Dan Leary says users could get a 2X reduction in Exchange disk storage needs and up to a 4X reduction with SQL Server.
The secondary data, consisting of snapshots, is deduplicated, and compressed and changed blocks replicated across a LAN or WAN link to a disaster-recovery (DR) CS-Series product. This maintains a mountable exact copy of the primary CS-Series array and so recovery from a primary failure takes minutes instead of hours. There is effectively no backup window as there is no need for backup software at all; snapshots replacing it.
Up to 90 days of application snapshot data can be held in the secondary storage. Leary says there are application and virtual machine-consistent backups for Microsoft and VMware environments, and the CS-Series products are optimised for Exchange, SQL Server, VMware and Hyper-V environments.
Applications issuing the storage are thinly provisioned and popular apps like Exchange and SQL Server can be provisioned, including data protection attributes, in three steps using templates. There is a zero-copy cloning facility, good for database test and development and also creating virtual desktop images, with a database clonable in seconds.
The whole system is claimed to be easy to use, with Leary saying: "We've extended EqualLogic simplicity from primary storage to backup and off-site. … We integrate with Microsoft VSS [and] take snapshots of applications in a consistent state." Users can self-restore files: "We offer a 60 - 90 day backup window. They never need to restore using traditional heavyweight processes."
Nimble Storage calls its design a Cache-Accelerated Sequential Layout (CASL) and Leary says random writes are bulked together and turned into sequential writes: "It collects deduped blocks into longer segments for writing to flash or disk… Writing in large sequences of blocks increases write speed and extends flash life. It's also an ideal way to write data to SATA disks, which don't like to seek… We never write data randomly."
There is an all-in-one licensing model for the array hardware and software features. Leary says Nimble Storage's products represent: "Savings of 60 - 70 - 75 per cent of the capital cost of purchasing systems from other vendors."
However, customers still have to buy two boxes as without a second, remote DR CS-Series, there is no protection against data loss if the first CS-Series fails.
The CS220 has 9TB of primary SATA storage and 108TB of secondary SATA storage and costs around $50,000. The CS240 has 18TB of primary SATA disk, 216TB of secondary SATA capacity, and costs around $100,000. They will be generally available in August and Nimble Storage is setting up a reseller channel. A peer-to-peer clustering capability will come out in a v1.1 software release.
We might speculate about a file access option coming after that, as combining iSCSI block and file storage is a common supplier tactic. ®