4 ms·
Exactly, especially if he is using snapshots, BTRFS can cause serious write amplification for frequently snapshotted and changed data.
by trillic 5y ago
Exactly, especially if he is using snapshots, BTRFS can cause serious write amplification for frequently snapshotted and changed data.
- etbe 5y agoI'm not sure it makes a lot of difference unless you have hundreds of snapshots. The way changes work to BTRFS is that every change without snapshots does most of the same stuff that a change with snapshots does. If however you have many snapshots (more than 500 according to rumours, I've seen it with over 1000) performance can get really bad. If your script to make snapshot backups works and the script to remove old ones doesn't work properly then the system runs fine for months and suddenly goes ridiculously slow. A VM with a BTRFS filesystem running on a host using BTRFS gives serious write amplification. But if the real storage is SSD then it's not too bad.
- MertsA 5y agoWhat's nice is that as of Linux 5.16 BTRFS now supports ZNS (https://zonedstorage.io/ https://zonedstorage.io/) to drastically reduce write amplification compared to traditional SSDs by bypassing a lot of the FTL and moving to an interface that's similar to host managed SMR drives.