Building A Low-Cost Btrfs SSD RAID Array For $80

Written by Michael Larabel in Storage on 2 February 2016. Page 1 of 3. 21 Comments

With the falling prices of solid-state storage, it's becoming increasingly affordable to build a RAID array of SSDs. I have delivered many Btrfs RAID benchmarks on Phoronix over the years while today I have some fresh RAID0 and RAID1 numbers for Btrfs atop the latest Linux 4.5 development kernel when using two low-cost SSDs that retail for just around $40 USD a piece.

The drives I managed to get for $39 each last week were the SanDisk SSD Plus SDSSDA-120G-G25 drives, while since then they increased to price to around $44 USD on Amazon or $66 for the 240GB version. The SanDisk SSD Plus 120GB drive is rated for sequential reads up to 520MB/s, sequential writes up to 180MB/s, and a rating of 1.7 million hours MTBF. The SanDisk SATA 3.0 SSD is backed by a three year warranty and currently boasts a 4.5-star rating on from 762+ customer reviews.

With having good experience with SanDisk SSDs in the past while being very affordable, when seeing these SSDs at a rate of 3GB per $1, I decided to order two of them as I'm still replacing a few remaining HDD-based test systems with solid-state storage. Before commissioning them, I ran some fresh RAID 0/1 benchmarks with these SanDisk SSDs using Btrfs' native RAID functionality with the in-development Linux 4.5 kernel.

Btrfs Linux SSD RAID0 RAID1 Benchmarks

So for some fresh reference Btrfs RAID 0/1 SSD benchmarks, I ran tests in the following configurations: a single SanDisk SSD Plus, two SanDisk SSD Plus in RAID 0, two SanDisk SSD Plus in RAID 1, and two SanDisk SSD Plus in RAID 1 while enabling the LZO native transparent file-system compression. The native file-system compression support tends to do too well during the synthetic disk benchmarks to the easily compressable data, but it's interesting nevertheless if you are thinking about a RAID1 configuration for better redundancy while hoping to get a bit better performance by utilizing the file-system compression. All of the tests were done with the Btrfs stock mount options, which includes automatically setting the ssd and ssd_spread options for these non-rotating disks.

All of these Btrfs low-cost RAID benchmarks were done in a fully-automated and reproducible manner using the open-source Phoronix Test Suite benchmarking software. On the following pages are these latest Btrfs RAID reference results from the Linux 4.5-rc2 kernel.

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