Linux software vs hardware RAID
There’s an interesting list by a Linux kernel contributor about the benefits of Linux software RAID versus hardware RAID.
One issue I wasn’t aware of:
Many ATA-based hardware RAID solutions either (a) fail to manage disk lifetimes via SMART, or (b) manage SMART diagnostics in a non-standard way.
The Linux smartmontools (“smartctl” command and “smartd” daemon) are great tools for knowing when a drive should be replaced. Almost all ATA and SATA drives now support some form of SMART… any controller that interferes with that data is dangerous.
Linux has excellent software RAID features that, in my experience, is often faster than hardware controllers. It’s certainly more flexible in terms of mixing different disk types, plus a whole lot cheaper to implement. Small organizations reluctant to spend on hardware RAID can usually be convinced to at least buy one more disk and set up software mirroring… a cheap and relatively easy way to increase the availability of even the smallest system.
Though it’s getting a little old, the definitive book on Linux RAID is O’Reilly’s “Managing RAID on Linux“. There’s also the slightly more up-to-date “Software RAID HOWTO” hosted at the Linux Documentation Project, plus many, many articles scattered around the web.
Update: For more on Linux RAID, check out Setting up software RAID in Ubuntu Server
Related posts:
- Setting up software RAID in Ubuntu Server
- Linux high availability clustering
- RAID in Ubuntu Server updated
Tags: availability, hardware, Linux, RAID, reliability, server security