On 5/9/07, Nick Holland <[EMAIL PROTECTED]> wrote:
If it was not obvious from my comments, I love softdeps. I have a siteXX.tgz file which does a few simple things, one of which is to change all mount points to use softdeps. One really does have to hunt a bit for relevant reasons not to use it. About the only place I can think of where I deliberately don't use it is on an e-mail archive system on the filled partitions which are mounted read-only. I can't tell you how many times I have forgot to install my siteXX file, started loading up /usr/src, and realized, "Dang, obviously no softdeps". At which point, I stop the checkout, fix the problem, reboot, and try again. Yes, the performance difference is that obvious, and it is faster to reboot than it is to wait it out.
I'm still curious about the issue of using softdep's when you have a raid card with write-cache (and battery)... I thought I'd do a simple test unpacking the ports.tar.gz with softdeps disabled/enabled, to see for myself. Without softdep enabled, I have the following: [EMAIL PROTECTED] time tar xzf ports.tar.gz 0.970u 2.120s 1:00.62 5.0% 0+0k 9821+210784io 6pf+0w [EMAIL PROTECTED] time rm -r ports 0.160u 1.390s 1:01.65 2.5% 0+0k 14994+126181io 17pf+0w About a minute to unpack and another minute to remove. With softdep enabled, I have the following: [EMAIL PROTECTED] time tar xzf ports.tar.gz 1.270u 2.100s 0:45.62 7.3% 0+0k 9874+66318io 59pf+0w [EMAIL PROTECTED] time rm -r ports 0.210u 1.230s 0:14.59 9.8% 0+0k 15741+22055io 17pf+0w 45 seconds to unpack and 15 seconds to remove. (I've repeated this a few times each way, and I always have roughly the same results.) With softdep enabled, there was more cpu time, but a noticeable decrease in total time. So, fair to say that even with raid+write-cache+battery that softdep's are beneficial (in terms of less disk time)? I'm more interested in maintaining disk-consistency, and with this setup, it looks like softdeps will still help with that also. Thanks again for all the info! -George
