Software RAID5 - beware!
 

My machine specs:
Pentium 3 600MHz
Ubuntu 6.10
Nvidia 64MB video card
software RAID1 40GB (2x40GB IDE)
software RAID5 1TB (3x500GB SATA)

Just letting you guys know that the software RAID 5 in Ubuntu 6.10/Debian can be unreliable. If you write too many files to your RAID5 drive it will stall the system, so remember to TEST THE SYSTEM. I thought it was my hardware, but memory tests and physical tests on the hardware show that everything is fine. I then decided to try CentOS server edition with RAID5 and it has been working flawlessly. If you google up RAID5 debian and ubuntu, you will see that other people have this problem.

Just curious to see if anybody else is using software RAID5 and if it has been working out for them or not.

Hardware RAID = Good. :cool:
Software RAID = Bad. :tisk:

:D

I agree with you. If I could afford a hardware RAID5, I would totally do it, but those things are a few hundred dollars. :( As you can see, my poor pentium 3 should get the upgrade. Fortunately it's just acting as a file server so it's not heavy duty. I am not familiar with CentOS so I guess now is the time to start learning.

I disagree with fukawi2. I generally recommend software RAID for smaller applications, as real hardware solutions are typically not cost effective. Hardware RAID is also not portable (between different controllers). Having run software RAID configurations for many years, they are very reliable.

That said, I've always used Redhat and Fedora for systems with software RAID. As CentOS is based on Redhat, I'm not surprised it worked. I personally have both software RAID-1 and software RAID-5, currently running on FC6.

Looking from the point of view of "How valuable is my data to our company?"... The cost of Hardware RAID-5 is justified every time :)

In a corporate environment, where high throughput is a requirement and a supply of spares is maintained on-site, absolutely.

In a home or small business, where any arbitrary set of block devices (IDE, SATA, SCSI, USB, Firewire) need to be RAIDed for capacity and reliability, software RAID rules.

For example, recently CompUSA dumped new 160GB external USB2.0/Firewire drives for $15 each. I was able to pick up 4, and created a hot-plug 440GB (available) RAID5 array for $60. You certainly wouldn't do that in a business environment (unless your I/O requirements would be met by 40MB/s drives and you had severe budgetary constraints), but for a home server, it doesn't get much better. Hardware RAID isn't even an option in this configuration, but the flexibility of software RAID allows you to just "make it work".

I really love Ubuntu, but this whole data loss incident with RAID has made me doubt the reliability of Ubuntu. The sad thing is that I currently have a major file server at work using Ubuntu 6.06. So far it has been working great *knock on wood*! I have to deploy another file server in 2-weeks and I think I am going to go with CentOS server edition (1-cd). I am willing to sacrifice usability for reliability.

does this affect recent ubuntu distributions?