Btrfs RAID Benchmarks With The Linux 4.4 Kernel On Samsung 850 SSDs

[phoronix]

Phoronix: Btrfs RAID Benchmarks With The Linux 4.4 Kernel On Samsung 850 SSDs

The latest Linux disk testing fun at Phoronix has been stressing two Samsung 850 EVO solid-state drives on the Linux 4.4 kernel when using the native RAID capabilities built into the Btrfs file-system.

http://www.phoronix.com/vr.php?view=22455

[caligula]

I recommend testing btrfs vs software md-raid. These numbers look really bad. Why would anyone consider raid0 if you get worse performance?

[bug77]

Afaik, you lose trim when running RAID configurations. Not worth it at all.

[caligula]

How about running btrfs raid on nas drives then? I don't really see any point in the benchmark other than to make btrfs / ssd disks look bad.

[winie]

Afaik, you lose trim when running RAID configurations. Not worth it at all.

No. It depends on what kind of RAID you're using.
It's only an issue if you're using motherboard raid on intel chipsets before 8 series or software raid with older versions of mdadm and linux.
The configuration tested here is btrs native "FILESYSTEM LEVEL" raid which supports trim just like a single disk btrfs partition.

[bug77]

No. It depends on what kind of RAID you're using.
It's only an issue if you're using motherboard raid on intel chipsets before 8 series or software raid with older versions of mdadm and linux.
The configuration tested here is btrs native "FILESYSTEM LEVEL" raid which supports trim just like a single disk btrfs partition.

Ah, ok. I knew newer intel chipsets are ok, but I thought the support is Windows-only. Glad to hear I was wrong.
Btw, does anyone know of RAID support on AMD chipsets (not that you'd be running AMD if you had the cash to run RAIDed SSDs).

[mmstick]

Ah, ok. I knew newer intel chipsets are ok, but I thought the support is Windows-only. Glad to hear I was wrong.
Btw, does anyone know of RAID support on AMD chipsets (not that you'd be running AMD if you had the cash to run RAIDed SSDs).

AMD motherboards often times have much more PCIe and SATA III ports than Intel motherboards at a fraction of the cost, and this has been true for a very long time, at least since the 890FX. This has always made AMD a superior choice for systems with large amounts of drives. RAID support is just fine on AMD motherboards, but you shouldn't be using motherboard Fake-RAID on Linux -- using Btrfs is much more ideal, especially with it's many features. When using RAID0 with Btrfs, it actually makes the metadata RAID1 while data is RAID0, so you can get a good amount of error-checking to ensure your files aren't corrupted.

[suberimakuri]

I recommend testing btrfs vs software md-raid. These numbers look really bad. Why would anyone consider raid0 if you get worse performance?

This would be great thanks.

[winie]

Ah, ok. I knew newer intel chipsets are ok, but I thought the support is Windows-only. Glad to hear I was wrong.
Btw, does anyone know of RAID support on AMD chipsets (not that you'd be running AMD if you had the cash to run RAIDed SSDs).

To clarify the chipset only matters if you're using bios raid.
I mentioned three kinds of raid (there is also hardware accelerated raid cards)
First is chipset provided raid which you should definitly avoid but works the same regardless of os because it's abstracted from the os and the os only sees one disk.
Second is os level raid which would be mdadm for linux and it supports trim if you're not running an ancient version.
And third is filesystem level raid which i recommend because it's easiest to setup and recover in case of failure and it's portable (no linux configuration; just connect the disks to another system and mount it).
For a quick start you can use this command to fomat two partitions as a btrfs raid0:
sudo mkfs.btrfs -d raid0 /dev/sda1 /dev/sdb1
To mount a multi-device btrfs filesystem just mount one of them:
sudo mount /dev/sda1 /mnt

[R00KIE]

Seeing noatime being tested left me curious about how lazytime would compare to relatime and noatime.