Austin S. Hemmelgarn posted on Wed, 20 Jan 2016 10:39:58 -0500 as excerpted: > On 2016-01-20 10:33, Al wrote: >> [very quietly] I've had autodefrag out of my mount options for a long >> while now. Is that still the recommended position? > I think it really depends on what you're doing. In my case, I usually > have it on, and the only issue I've ever seen is that Chrome sometimes > loads pages from local cache slower than it should be. I also don't use > ridiculous numbers of snapshots either (I use them only to get a stable > view of the filesystem when generating a backup), so I don't have much > experience with how they interact with autodefrag. I use autodefrag here too. The situations where autodefrag won't make sense are going to be ones where people are doing large files (half-gig plus) with heavy rewrites -- typically large database and VM image files. Those need other measures, generally nocow, lower snapshotting frequencies, and periodic manual defrag. Autodefrag with heavy snapshotting is more of an open question, as would be autodefrag on SSD. I'd personally argue that the benefits of autodefrag exceed the down sides in these cases, but can easily see how some may argue otherwise, so it's admin's call, after suitable testing if they care enough about it to do that. Autodefrag is definitely recommended for "desktop" usage (particularly on non-ssd), however, where the largest random-rewrite-pattern files are the smaller (typically under quarter GiB) sqlite type databases common to firefox/chrome/thunderbird/evolution/etc, as that's where autodefrag does its best. My typical usage is pretty close to this "desktop" usage, tho I am on SSD, so I use autodefrag. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
