Re: [9fans] fossil+venti performance question

2015-05-04 Thread David du Colombier
I'm experiencing the same issue as well. When I launch vacfs on the same machine as Venti, reading is very slow. When I launch vacfs on another Plan 9 or Unix machine, reading is fast. I've just made some measurements when reading a file: Vacfs running on the same machine as Venti: 151 KB/s Vacf

Re: [9fans] fossil+venti performance question

2015-05-04 Thread Aram Hăvărneanu
I have seen the same problem a few years back on about half of my machines. The other half were fine. There was a 1000x difference in performance between the good and bad machines. I have spent some time debugging this, but unfortunately, I couldn't find the root cause, and I just stopped using fos

Re: [9fans] fossil+venti performance question

2015-05-04 Thread Anthony Sorace
The reason, in general: In a fossil+venti setup, fossil runs (basically) as a cache for venti. If your access just hits fossil, it’ll be quick; if not, you hit the (significantly slower) venti. I bet if you re-run the same test twice in a row, you’re going to see dramatically improved performance.

[9fans] fossil+venti performance question

2015-05-04 Thread KADOTA Kyohei
Hello, fans. I’m running Plan 9(labs) on public QEMU/KVM service. My Plan 9 system has a slow read performance problem. I ran 'iostats md5sum /386/9pcf’, DMA is on, read result is 150KB/s. but write performance is fast. My Plan 9 system has a 200GB HDD, formatted with fossil+venti. disk layout is