Mirrored Raid Question

[bob4432]

i have never used raid but need some redundancy for a setup i am contemplating. my quick question is when one drive fails, how are you notified? is it at bootup?

 

[Vegito]

In real RAID, if one drive fails, the management software emails you providing you set that up, writes event log, etc.. usually you dont see any problems..

In wanna be RAID, you boot up and you see one drive fail and you say oh snap.. im fubared..

 

[bob4432]

Originally posted by: forcesho
In real RAID, if one drive fails, the management software emails you providing you set that up, writes event log, etc.. usually you dont see any problems..

In wanna be RAID, you boot up and you see one drive fail and you say oh snap.. im fubared..

what is the difference in a real and wanna be?

 

[Vegito]

SCSI raid are usually bundle with management software, much better in fault tolerance..

ide are the cheap crap that comes with mobo.. real scsi raid, you can pull drives out and move it to another system to recover, etc.. ide raid, you pull a drive out, half the time it doesn't work or you end up losing stuff anyway.. ide are the software raid with no real xor engines.. scsi raid are done on the controller not by software/cpu

 

[bob4432]

what about the ide raid cards, still crap?

 

[Matthias99]

Originally posted by: bob4432
what about the ide raid cards, still crap?

Despite claims above to the contrary, a lot of IDE/SATA RAID controllers work just fine. The really dirt-cheap RAID controllers (including most if not all onboard ones) do software RAID, which, while generally pretty good, is not quite as reliable as a controller that does everything onboard (and it also increases your CPU load a bit). An unstable CPU or bad memory can easily screw up software RAID, whereas hardware RAID is more likely to survive intact, since it has its own onboard processor and ECC memory.

Management software implementations are up to the vendor; you can have SCSI RAID with crap software, and IDE/SATA RAID with excellent software (active monitoring, ability to make online configuration changes, email notification, etc.). Sweeping generalizations about them are not helpful.

 

[bob4432]

what would you recommend for a ide raid setup?

 

[Matthias99]

Originally posted by: bob4432
what would you recommend for a ide raid setup?

Well, I had just about settled on the Promise S150-SX4 (4-port SATA, hardware RAID5), but then they went and discontinued it. And apparently their software doesn't support online capacity expansion of your drives (you can add more disks to an array, but you can't swap out for bigger disks and then expand a RAID5 array to use the extra space).

Now I'm probably going to get the LSI MegaRAID SATA 150-4 (also 4-port SATA, hardware RAID5).

If you just want RAID1, I'm not sure what the cheapest/best solution would be. Highpoint and Promise both have what appear to be fairly good, cheap 2-port SATA RAID controllers (Highpoint is software, not sure about Promise).

 

[bob4432]

Originally posted by: Matthias99

Originally posted by: bob4432
what would you recommend for a ide raid setup?

Well, I had just about settled on the Promise S150-SX4 (4-port SATA, hardware RAID5), but then they went and discontinued it. And apparently their software doesn't support online capacity expansion of your drives (you can add more disks to an array, but you can't swap out for bigger disks and then expand a RAID5 array to use the extra space).

Now I'm probably going to get the LSI MegaRAID SATA 150-4 (also 4-port SATA, hardware RAID5).

If you just want RAID1, I'm not sure what the cheapest/best solution would be. Highpoint and Promise both have what appear to be fairly good, cheap 2-port SATA RAID controllers (Highpoint is software, not sure about Promise).

do they offer the same thing in pata?

 

[Matthias99]

Originally posted by: bob4432
do they offer the same thing in pata?

Probably? I've been looking at SATA stuff recently, if that wasn't obvious. I'm sure storagereview.com or a Google search would turn up plenty of info.

 

[bob4432]

Originally posted by: Matthias99

Originally posted by: bob4432
do they offer the same thing in pata?

Probably? I've been looking at SATA stuff recently, if that wasn't obvious. I'm sure storagereview.com or a Google search would turn up plenty of info.

thanks

 

[Thegonagle]

I am using the built-in VIA IDE (PATA) RAID controller on my Asus P4P800-Deluxe. I was able to rebuild the RAID 1 array without any major problems that I can remember. Unfortunately, the mirror had pretty much corrupted itself after a few months (probably because my cats were running around and crashed into my open case causing a reset while I was using the system); there was no physical problem with either drive because it's been running fine now for a year after I rebuilt the array. There is software that runs in Windows and pops up a warning if the VIA hardware detects a problem. The rebuilding process (and initial setup process) is taken care of through a ROM-based setup utility. I would stay away from any RAID solutions that only run in software (if they exist)--what would you do if the system won't boot?

The extent of my experience with RAID is with my system and its VIA hardware PATA IDE RAID controller. I haven't had a real disk failure yet; I've only that one problem with the mirror losing synchronization. Fixing it was a simple matter of telling the setup utility to resynchronize the mirror, and then waiting for it to copy. (I imagine it would be the same if I did need to replace one of the drives though.)