From mboxrd@z Thu Jan 1 00:00:00 1970 From: jason-tuhs@shalott.net (jason-tuhs@shalott.net) Date: Tue, 21 Feb 2017 17:33:06 -0800 (PST) Subject: [TUHS] Mach for i386 / Mt Xinu or other In-Reply-To: References: <20170221120218.E07BA18C10B@mercury.lcs.mit.edu> <20170221164728.GZ20341@mcvoy.com> Message-ID: > I got to thinking about the file system sync vs. order argument as a > result of this interesting discussion. > [...] > What we discovered, when we added the Linux cluster, was that building > power was really terrible. We had not realized it with the freebsd > cluster because it tended to cleanly recover from unplanned nasty power > cycles. But the Linux cluster tended to always have a small number of > nodes that did not get through fsck. Soft updates was available in 1998. Were you running that? Surprised it hasn't come up already in this discussion; I've been waiting for someone to mention it. http://www.mckusick.com/softdep/ There was some licensing issue with it in the early days: it was freely available and free to use, but McKusick wanted a chance to try to sell it to a commercial unix vendor as well. But he ended up BSD-licensing it a couple years later. The original README from the FreeBSD source tree: https://svnweb.freebsd.org/base/release/3.0.0/contrib/sys/softupdates/README?revision=42952&view=co Anyway, it solved the on-disk consistency problem and boosted performance as well. I enabled it on all my systems. -Jason