[H-GEN] SCSI Raid Cards

[David Jericho]

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David Jericho wrote:

A load of irrelevant twaddle. I haven't had my coffee yet, and I'm still 
recovering from the weekend. I'll try this again. (Although, if you are 
looking for _IDE_ controllers, the advice is pertinent).

James Collins wrote:

>     Any Humbug folks had any experience with SCSI Raid cards and 
> Linux? Any
> recommendations on which one to buy? Or should I just stick to Linux's
> Software Raid?

Depends on your budget, and what you're wanting out of a RAID controller.

If you don't mind your machine exhibiting unusual behaviour around the 
time of a drive death, stick with software RAID and a multichannel SCSI 
card(s). Your machine could lock, reboot, or just display exceptional 
lack of performance when the drive dies. Having said that, the code has 
come a long way, and a single failure on the device can be enough to 
kick the device over into a failed state, thereby removing the kernel's 
access.

If you wanting more, like battery backup, higher performance, removal of 
IO impact on the machine due to reading and writing, and possibly more 
reliable hot swap, hardware RAID maybe the go for you. Keep in mind that 
  hardware RAID can get very expensive very quickly.

One solution to investigate is a RAID chassis. Basically you plug a 
single non-intelligent SCSI card into it (such as a 2940), and it does 
all the RAID stuff for you, taking care of failures, hot swap and the 
rest. They usually start at around $5k for a chassis that'll take a few 
drives. The upside is the array is just a single target, and there's no 
need for your machine to be aware of anything more than simple disk.

In the end, it really comes down to requirements. Asking what RAID 
controller to get is a bit like asking what car to buy, and not 
describing what you want to do with it :)

-- 
David Jericho
Systems Administrator, Plugged In Software


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