4 ms·
You should give "How to Fragment Your File System" by a lot of people a read. http://csis.pace.edu/~jyuan2/paper/betrfs5.pdf http://csis.pace.edu/~jyuan2/paper
by JaimeThompson 5y ago
You should give "How to Fragment Your File System" by a lot of people a read.
http://csis.pace.edu/~jyuan2/paper/betrfs5.pdf http://csis.pace.edu/~jyuan2/paper/betrfs5.pdf
"In this article, we demonstrate that modern file systems can still suffer from fragmentation under representative workloads, and we describe a simple method for quickly inducing aging.
Our results suggest that fragmentation can be a first-order performance concern—some file systems slow down by over 20x over the course of our experiments. We show that fragmentation causes performance declines on both hard drives and SSDs, when there is plentiful cache available, and even on large disks with ample free space."
- anyfoo 5y agoGuess I was myself part of what the second sentence mentions: "System implementers and users alike treat aging as a solved problem." :)
- KennyBlanken 5y agoThe web is full of people shouting "_____ filesytem doesn't get fragmented!" Apparently they've never let a filesystem get above 70% full or so, especially one on a fileserver that has seen years of daily use by a dozen+ people. I've heard it for HFS, HFS+, XFS, ext3, ext4, etc and every time it was an lie. Every filesystem fragments after regular use unless you have a fuckton of free space. It's pretty hard to justify to one's bosses over-provisioning disk space to enough of a degree to render fragmentation unlikely, and users just expand their data to fit it anyway.
- sumtechguy 5y ago2,281 extents found hmm that does not seem right and off by an order 10x...