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What type of RAID to do ?

By noorazman ·
Dear all,
I have compaq ML 330 with 2 scsi hdd. One hdd is for windows 2003 and applications. The other hdd is only for data. I want to do RAID and will buy smart array 641. How many additional hdd i have to buy ? ( 2 NHP bay is occupied, 3 HP bay un-occupied)
What suitable RAID should i do ? (i will running oracle & wish to have on-line standby hdd)

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by darts32 In reply to What type of RAID to do ?

I would run either Raid 1 or 5 for reasons of recovery and minimize data loss.

Level 1 is also referred to as "Mirroring".
A RAID 1 array is very simple, two or more disks act as one logical disk, and data is mirrored between the disks. If you have an array consisting of two 36 GB disks, you will end up with a logical disk of 36 GB, with data being stored on both the physical disks. Hence one of the physical disks can fail, and the array will keep working, and if the disks are hot-swappable, which is the case with most SCSI RAID setups, the failed disk can be swapped for a new disk, and the controller will synch the data between the disks, restoring the array to full functionality, with no downtime. RAID 1 also increases the read performance since both disks can be read at once, while write performance will be more or less identical to that of one single disk. RAID 1 is a good cheap way to achieve good read performance, as well as redundancy.

3 or more disks a required for a RAID 5 array. RAID 5 stores parity information (unlike RAID 1 which stores data redundantly) across the disks in the array, this information can then be used to rebuild lost data in case of disk failure.

So for Raid 1 you will need 2 more HDD's and 4 more for Raid 5.

Hope this helps

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by sgt_shultz In reply to What type of RAID to do ?

does a controller such as smart array 641 require hard disks of the same size and preferable the same model?

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by Mark In reply to What type of RAID to do ?

Most popular is RAID 5 with 3 Drives. If you want better performance, just use more drives.

For best performance, use RAID 10. The controller is usually cheaper, but you will need 4 drives and will sacrifice available space.

It's all a question of what you are trying to accomplish. There are trade offs with all configurations of RAID.

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