Chris Worley wrote:
On Dec 4, 2007 11:49 AM, Aaron Kulkis
wrote: Chris Worley wrote:
On Dec 4, 2007 10:22 AM, Jc Polanycia
wrote: Off topic, as I seldom partition anything (unpartitioned drives perform best), but, you're setting yourself up for disaster using LVM (any corruption to the LVM layer is not recoverable... you'll loose everything... been there done that), and the performance is poor, and MD RAID5/6 devices can be grown (add more disks).
Chris
Fair enough. I appreciate the input because I haven't run across any real-world stories about LVM corruption. I have personally encountered corruption problems with RAID5/6 as well as problems with decreased performance as a RAID5 structure gets more members added to it. I saw some RAID6 issues last year, so I use RAID5... but recent tests have shown MD RAID6 as solid.
"Decreased performance as more members get added to it"? Bull!!! I'm guessing you have another bottleneck that has led you to this conclusion.
While the performance increase doesn't scale linearly as disks are added (some CPU verhead is added with each additional drive), the more disks, the better the performance. I'm sure there is some Amdahl's law limit to the increased performance scalability, but I run RAIDS up to 12 drives, and see performance added w/ each new member.
You're hallucinating. That defies basic information theory.
Your assertion is akin to suggesting that you power your computers with a perpetual motion machine (despite the fact that such would violate the 1st, 2nd, and 3rd laws of thermodynamics).
Amdahl's law defies "Information theory"? How so?
If you've got one disk that can perform at 70MB/s on a 320MB/s bus, then on that bus you should be able to stripe at least four drives with less-than-linear scalability... add more busses w/ more dirves... more scalability... of course, not linear. Add caching effects, and get superlinear scalabiltiy (but that doesn't count).
Your analysis is flawed because it assumes zero time for disk-head seeks.
I do believe your the one who's full of s***.
I'm not the one making crazy statements that rely on disk-heads using instant teleportation from track to track. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org