Fast, reliable, cheap: pick 2? ZFS brings all!
By Frederic Pariente on Oct 24, 2008
Today's post is the first instance of an on-going series of technology adoption proofpoints. They are short real-life success stories about our application partners leveraging Sun technologies and innovation to create value for the end-customer. They will be, for the most part, the result of our developer support work at ISV Engineering. Unless there had been some public coverage of that work, proofpoints will be anonymized; only the industry and application segment will be identified --so you can still relate them to your own market and customers. So there we go...
After a server crash at a major European bank, two companies got a phone call; Sun because the logo is on the box, and the ISV whose application --a SWIFTnet messaging platform-- was running on it. The call came very quickly because the crash had led to corrupted data. Our joint investigation showed that one VxFS extend --the bank was using the Veritas File System 4.1-- contained old/bad financial data mixed with correct data. The problem was believed to happen after a new VxFS extend was allocated but before its metadata was written. By default, VxFS does not zero newly-allocated extends. For business environments where data integrity is critical, Veritas recommends the mount -o blkclear option that guarantees that uninitialized data does not appear in a file. That solution induced however an 15% performance loss with the application, unacceptable for the customer, and increased disk footprint of the C-ISAM (embedded database) data files.
The Solaris 10 operating system and ZFS filesystem was tested as an alternative solution and used as is with no additional flag. Due to its guaranteed data integrity, application data was found 100% correct after a stringent series of (20) crash tests. The application performance increased by 10% with ZFS compared to VxFS. In addition, the application's cold recovery process, which is started after a power failure, was taking only 15 seconds on ZFS when all C-ISAM database files have been checked. Finally, it was demonstrated that the ZFS built-in snapshot mechanism could be used to implement a Point-in-Time solution eliminating the need of expensive storage with snapshot capabilities.
As a result of this joint engineering work, the ISV listed ZFS as the recommended filesystem to all its customers. Based on this recommendation, customers have migrated to Solaris 10, from earlier releases of Solaris on Sparc, or are planning to do it. Based on ZFS, which is an integral part of the (free) Solaris and OpenSolaris distributions, the ISV solution is more competitive, guaranteeing data integrity --equals higher availability-- and reducing cost of ownership --no VxFS license, no expensive storage-- while delivering full performance.