Btrfs RAID Tests On Linux 4.8

[phoronix]

Phoronix: Btrfs RAID Tests On Linux 4.8

Recently I've been carrying out a number of Btrfs RAID tests on Linux 4.7 while this past weekend I ran some comparison tests using the Linux 4.8 Git kernel...

http://www.phoronix.com/scan.php?page=news_item&px=Btrfs-RAID-Linux-4.8

[thelongdivider]

Jeez, I hope they don't mess up single disk performance in the process. It's only rc2 so I remain hopeful.

[ormaaj]

I still remember 7 years ago doing a Gentoo install and thinking "Gee btrfs sounds neat, but it sure is slow. Maybe I'll wait a few releases..."

[ferry]

It really is neat.

And we only notice it to be slow (raid10) when we update packages (.deb) using synaptics/apt or run a VM.

I don't think the benchmarks properly reflect that in many use cases (except databases like postgres, sqlite) the disk being 50% faster or slower is hardly noticeable.

While on our server (raid10 + 100 snapshots) apt is running maybe 10x slower than on my desktop (single + 0 snapshots). While on the desktop apt may be unnoticeable slower than ext4.

Michael, can't you do a benchmark based on apt (lots of fsync), on btrfs with lots of snapshots. What I read is that btrfs can take a snapshot very fast, the downside being that other file operations with lots of snapshots can be very slow.

[gadnet]

do you think you would be able to compare xfs/ext4/f2fs+mdadm raid vs btrfs in same raid parity ?

[thelongdivider]

It really is neat.

And we only notice it to be slow (raid10) when we update packages (.deb) using synaptics/apt or run a VM.

I don't think the benchmarks properly reflect that in many use cases (except databases like postgres, sqlite) the disk being 50% faster or slower is hardly noticeable.

While on our server (raid10 + 100 snapshots) apt is running maybe 10x slower than on my desktop (single + 0 snapshots). While on the desktop apt may be unnoticeable slower than ext4.

Michael, can't you do a benchmark based on apt (lots of fsync), on btrfs with lots of snapshots. What I read is that btrfs can take a snapshot very fast, the downside being that other file operations with lots of snapshots can be very slow.

50% seems a bit excessive. Most benchmarks put it at 80-90% of the speed. However, compression, snapshots, subvolumes, mounted scrubbing, defragmenting, etc. make up for this for me at least. It's an amazing filesystem which I hope improves in speed later, but even right now is adequate for both my hard drives and my NVME ssd.

I still remember 7 years ago doing a Gentoo install and thinking "Gee btrfs sounds neat, but it sure is slow. Maybe I'll wait a few releases..."

You should still try it, especially on hard drives.