raid

[Al Pollock]

Stting up 8 scsi hd 300 gig each.... two controler bds second controler has second controler.... want to set raid 1 (I think ) just mirror...software forces raid 0 or raid 0+1.................when I set up array is the first and second (0 and 1 ) seen as two distinct hd's or 1 hd ..first controler hd 0 and 1 ...second controler any combination 1 through 6 and third controler none or whatever is not in the 1 through 6...............so und confused you bettcha !!!!

[glc]

Exactly what do you WANT this array to do, what exact models are the drives, and what exact models are the controllers you have to work with?

[Al Pollock]

Hey GLC.............the drives are all Hewlett Packard...I don't have the unit right here in front of me so I can't exactly remember controlers ........they are in PCI -X slots and I think I recall them being like 6400 or 2400 not sure .....Basically want to set up the 0 drive with OS and 1 drive as a mirror..and then the next 6 as data and mirror alternately.....I think..
Like I mentioned in the original post the 0 and 1 are off one card the other six are off of the second card in which there are two ports.....

[glc]

Let's get the details if we could, please. I'd recommend, if possible, that you go ahead and RAID 1 the OS drive as you have indicated. Then, if possible, take the other 6 and set up a RAID 5 - with at least one hotspare. That's why I need the exact controller models to see if this is possible. I need the drive models to make sure you have the right connectors and cables. What OS is going to be on this thing?

[Al Pollock]

Only two choices for raid in the setup raid 0 and raid 0+1 I will have to wait to get back there to see what is there ..............and its snowing heavly here today, waitting for it to stop so I can go out and clear the driveway..and the old bones are a hurting........

[Al Pollock]

Forgot I have this monster running on 2003 server

[rspassey]

I would set up two 0+1 Arrays. Slightly faster speeds (slightly) and data redundancy incase of drive failure. Two sets of 4, one on each controler.

[glc]

This is assuming that both controllers are capable of 0+1. You will be able to partition each array separately - it will appear the same to you as 2 simple hard drives. This would be a LOT simpler than dealing with 4 separate arrays - and we don't know if either controller is capable of managing more than one array on it anyway.

If either controller is capable of RAID 5, this is the *best* way to manage a server. RAID 5 is striping with a parity drive - it has the storage capacity of the array minus 1 drive, if a drive fails, it can be replaced and the array rebuilt without data loss. It requires a minimum of 3 drives but will perform poorly unless you add one more drive for a total of 4 - and you can add even more. Some controllers even support hotspares - additional drives not in the active array, if a drive fails the array rebuilds using the hotspare on the fly. Then you remove the failed drive, replace it, and make the replacement a new hotspare.

I have a customer with 2 servers I built for him this way. His OS is on a small IDE drive and his data array is a 8 drive SATA RAID 5 array. I used eight WD 250gb Raid Edition drives and an Adaptec 8 port SATA RAID controller. I built a 6 drive array with 2 hotspares. The array has the capacity of 5 drives - 1.13Tb after slop - each drive is 232 actual gb. We have an image of the IDE drive stored on the array in case it goes down and has to be replaced instead of using RAID 1.

We lost one array drive about a week after the build on one of the servers - we kicked in a hotspare using the Windows management utility and rebuilt the array on the fly - then reformatted the failed drive and made it a new hotspare - all without a reboot. We don't know why the drive dumped, but the array has worked flawlessly since. Unless you have the management software set to e-mail you in case of a failure or you keep an eye on it, the only way you will know of a drive failure is slow performance. A RAID 5 array with a failed drive still works, just a lot slower because it has to check parity constantly and recreate the data. Some controllers will automatically kick in a hotspare and rebuild in the background.

[Al Pollock]

Hey GLC.......The unit is a HP Proliant ML350...

You can have only one array on the first card...There are two drives on it and it can be 0 or 0 +1.........I tried swaping those two drives and the machine will boot either way failed to notice light indicators to see which HD was booting ...it looked like it boot from eithert drive although that doesn't seem right with raid 0????? What do I know????

[glc]

Raid 0 is a striped pair, capacity of both drives seen as one drive. Raid 1 is a mirrored pair, seen as one drive, capacity of only one drive. 0+1 is a mirrored striped pair - 4 drives with the capacity of 2, again seen as only one drive.