admin's blog
CNBC homepage reacting to Dow dropping to 7600
Screenshot from CNBC as Dow drops below 7600.
KernelTrap: Killing Tasks On Frozen NFS Mounts
"I've long hated the non-killability of tasks accessing a dead NFS server," Matthew Wilcox said along with a prototype patch to fix the issue based on a 2002 posting by Linus Torvalds. Matthew added, "I've only added one real user of the killable concept to this patch -- try_lock_page(). However, this is enough for 'cat */*/*' to be killable with a ^C when I unplug the ethernet cord between it and the nfs server."
Linus responded favorably to the patch, "hey, I obviously approve. And the patch looks simple." He went on to suggest that he was interested in merging the patch during the next merge window, "feel free to re-submit after 2.6.23 is out the door, I don't think anybody will really complain. Any NFS user will know why something like this can be really nice."
read more | rsync.net - Offsite Unix Backups
Dave@NetApp: Oracle Optimizes Its Database for NFS
NFS has become critical to data center grid environments. As a result, Oracle has optimized its code specifically for NFS. Instead of relying on the operating system, Oracle’s Direct NFS Client generates NFS requests directly from the database.
Direct NFS was inspired by experience at Oracle’s Austin Data Center. Oracle uses NFS to run its applications on tens of thousands of Linux servers accessing many petabytes of NetApp storage. In 2005 they had 12,000 Linux servers and 3 petabytes of NetApp storage. Today’s numbers aren’t public, but they are much larger.
When an operating system capability becomes sufficiently
important, Oracle pulls it into the database. Memory management became
critical, so Oracle said, “Just give me the raw pages, and I’ll manage them
myself.” Disk caching became critical, and Oracle said, “Just give me the raw
disk blocks, and I’ll cache them myself.” Now NFS has become critical, so Oracle
says, “Just give me a raw TCP/IP socket, and I’ll generate NFS requests myself.”
Steve Kleiman has argued that as Oracle becomes more sophisticated, the operating system becomes little more than a device driver framework that gives the database raw access to the hardware. That sheds new light on Oracle’s Unbreakable Linux program.
Dave@NetApp: Green Data Centers and Solar Villages (Change is Most Likely When Heart and Wallet Align)
The Solar Electric Light Fund (SELF) provides solar lights to poor villages in developing countries. The trouble with solar is that it doesn’t work at night. (D’oh!). Off-grid solar is impractical for most first world houses because it takes expensive batteries to run 100-watt light bulbs and big TVs. When the competition is a dim and smoky kerosene lamp, small/cheap batteries work just fine. The payback is surprisingly fast; villagers already pay $5-10 a month for kerosene. The unexpected result is that solar power today is economically feasible for poor rural villages, but not for first world homes. Just as some developing countries have gone straight to cell phones, skipping landlines, rural villages may skip the power-grid and go straight to solar.
I must be a capitalist at heart: I love that people often want to do the right thing, but I believe that large-scale change is much more likely when supported by good economics. SELF’s approach is so powerful because using solar instead of oil feels like the right thing, but they have improved the odds of success by focusing where there is a positive return on investment (ROI). Once they show the way, their approach should become a virtuous circle, spreading rapidly without more charity. SELF gets the ball rolling, gets a local industry going, and then moves on to the next country.
I believe that a similar dynamic will drive power savings in corporate data centers. In theory, corporations may want to do the right thing by running green data centers, but it’ll be the economic benefits that drive large-scale change. This has been such a hot topic lately that the EPA – under direction from congress – is about to release a report on data center energy efficiency. In drafting the report, the EPA was interested in hearing what NetApp did to save power in our Sunnyvale data center.
Rich Teer: Sysadmin stuff
I received my August copy of Sysadmin Magazine a few days ago, and I wondered why it felt a bit thinner than usual. The answer was to be found in Amber's editorial: Sysadmin Mag has ceased to be. It is bereft of life, it's pushing up the daisies. It is an ex-magazine! I'll miss it--I've been reading Sysadmin for years, and I've even had an article or two published in it. [PlanetSolaris]
