Re: Weird blocks at fsync() calls using md
From: Sander Smeenk <hidden>
Date: 2006-07-28 13:38:11
Quoting Neil Brown (neilb@suse.de):
quoted
13:28:07.011717 fsync(4) = 0 13:28:12.748252 open("js_gen.pl", O_WRONLY|O_CREAT|O_TRUNC, 0770) = 3 13:28:12.748427 write(3, "#!/usr/bin/perl -w\nuse strict;\nu"..., 2189) = 2189 13:28:12.748506 fsync(3) = 0 13:28:13.006702 close(3) = 0Yes, it's weird. The sync of the .swp file takes a lot longer than the fsync of the actual file you are saving....
Yup. And it's always the fsync() on the .swp file too ;)
I have this theory that there might be some odd interaction between md and the drive scheduler.
Well, i never really understood the big difference between the three models. I used to do deadline on servers, but that turned out to be REALLY bad (at least on our intranet server). Caused major load on writes, made NFS b0rk, and when i switched it back to Anticipatory it was all normal again, so that's what i used afterwards. Using CFQ gives the same, maybe even worse results. As does Deadline :S Strange huh! Only this time the fsync() wasn't on the .swp file but on the "real" file after writing it's contents... Kind regards, Sander. -- | He broke into song because he couldn't find the key. | 1024D/08CEC94D - 34B3 3314 B146 E13C 70C8 9BDB D463 7E41 08CE C94D