[Asterisk-Users] Hardware for Asterisk

[Robert L Mathews]

At 1/16/04 7:25 AM, Andrew Kohlsmith <akohlsmith-asterisk at benshaw.com> 
wrote:

>That's pure bullshit -- I use software RAID *specifically* because I value 
>my data.  I don't want to buy two hardaware RAID controllers to have one 
>sit on the shelf just in case the first dies... and if the second dies 
>you're SOL because they've lasted long enough that they're no longer 
>available.  Linux software RAID is available on any Linux system and if the 
>system blows up I can put the drives in another system and *not* worry 
>about it not being detected.

Yeah, I couldn't agree more.

We originally thought hardware RAID was the way to go, and we bought a 
couple of fully loaded Dell PowerEdge 2550s with SCSI hardware RAID 5 
arrays at about $4500 a pop. We also bought a PowerEdge 600SC for around 
$900 with lots of disk space to use as a network backup machine (backing 
up the 2550s) with Linux software RAID 5. I've also had a crappy old 
desktop machine running Linux software RAID 1 for a couple of years.

It turns out that the software RAID is just as reliable (more so, in fact 
-- we have had a number of lockups on the 2550s that appear to be due to 
the hardware RAID subsystem locking up, and the software RAID machines 
have never done that, even though the backup server does more disk I/O 
than the others). The software RAID on the 600SC is faster than the 
hardware RAID in bonnie tests.

In addition, the Dell PowerEdge mailing lists are full of people with 
horror stories about their hardware RAID systems -- if that dies on mine, 
I'm screwed until I can convince Dell to come out and fix it (which they 
often won't do until they've spent hours on the phone with you trying 
various things).

We should have simply bought 4 600SCs (instead of 2 2550s and a 600SC), 
using one as a hot standby, and saved ourselves around $6000. In fact, 
we're planning on moving to that and selling the 2550s on eBay to improve 
our overall reliability. If the power supply, motherboard or RAM of a 
600SC dies, we can easily move the disks to the spare machine and be back 
up within a few minutes without relying on anyone else. In the worst case 
(RAID corruption/machine catches on fire), I'm still going to be okay, 
because I can restore from backups in a couple of hours.

The key thing to me is that at no point do we have to rely on any other 
company to get things up and running again, which is far more important 
than any putative risk of data corruption from software RAID (which I 
have not seen even under very heavy disk loads, and which I think is 
pretty much a myth these days; look at the Dell PowerEdge mailing lists 
if you think hardware RAID is more reliable -- those stories of hardware 
RAID problems from real users have scared me to the point that I'll never 
consider buying any sort of proprietary disk subsystem again).

-- 
Robert L Mathews, Tiger Technologies      http://www.tigertech.net/

"I am not able rightly to apprehend the kind of confusion of
 ideas that could provoke such a question."  -- Charles Babbage