- The Hitz report – Robin Harris at StorageMojo on the Sun-NetApp lawsuit:
NetApp’s biggest misperception is that WAFL is somehow central to the success they are enjoying today. That was true about 10 years ago. Guys, your average F500 CIO today could care less about WAFL.
NetApp is growing because they offer a compelling value proposition of quality products, relevant services and worldwide support. WAFL certainly supports that, but as NetApp execs note much of their recent success is due to the integration software that NetApp now offers.
WAFL is a small piece of the picture. Sun could copy it line for line and still not have a quarter of what NetApp offers.
NetApp faces challenges. Storage commoditization threatens all vendors traditional 60% gross margins. The GX integration is problematic and the bottom line benefit uncertain. EMC’s move into cloud file services is a clever flanking strategy.
An interesting opinion summed up nicely, I think.
- Saving and Restoring ZFS Snapshots to and from Amazon S3 – A ZFS to S3 workaround for the lack of persistent storage on EC2.
Archive for the ‘wafl’ tag
Hotlinks, 7/1/2008
On Parity Lost
I just finished reading a paper presented at FAST ‘08 from the University of Wisconsin, Madison (including the first and senior authors) and NetApp: Parity Lost and Parity Regained. The paper discusses the concept of parity pollution, where, in the words of the authors, “corrupt data in one block of a stripe spreads to other blocks through various parity calculations.”
With the NetApp employees as (middle) authors, the paper seems to have a slight orientation towards a NetApp perspective, but it does mention other filesystems, including ZFS both specifically and later by implication when discussing filesystems that use parental checksums, RAID and scrubbing to protect data. (Interestingly, the first specific mention of ZFS contains a gaffe where they refer to it using “RAID-4″ instead of RAID-Z.) The authors make an attempt to quantify the probability of loss or corruption – arriving at 0.486% probability per year for RAID-Scrub-Parent Checksum (implying ZFS) and 0.031% probability per year for RAID-Scrub-Block Checksum-Physical ID-Logical ID (WAFL) when using nearline drives in a 4 data disk, 1 parity disk RAID configuration and a read-write-scrub access pattern of 0.2-0.2-0.6.
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