RAID 5

[Rick DeZeeuw]

Should one install RAID 5 for SQL Server or just use separate hard drives, one for the data and one for the transaction log?

[Tjibbe Chris Kuipers]

On 12/20/98 7:15:09 PM, Rick DeZeeuw wrote:
> Should one install RAID 5 for SQL Server or just use separate hard drives,
> one for the data and one for the transaction log?

I think it would depend on what your main goal is. If it is performance then probably seperate drives would give you maximum performance. If it is safety, then you whould have to choose RAID-5.

On 12/22/98 12:19:15 AM, Tjibbe Chris Kuipers wrote:
> On 12/20/98 7:15:09 PM, Rick DeZeeuw wrote:
> Should one install RAID 5
> for SQL Server or just use separate hard drives,
> one for the data and
> one for the transaction log?

I think it would depend on what your main
> goal is. If it is performance then probably seperate drives would give you
> maximum performance. If it is safety, then you whould have to choose RAID-5.

Thanks for the info, Rick

[Don Romano]

On 12/20/98 7:15:09 PM, Rick DeZeeuw wrote:
> Should one install RAID 5 for SQL Server or just use separate hard drives,
> one for the data and one for the transaction log?

[Don Romano]

Sorry 'bout the previous reply... bad habit of hitting the 'Enter' key.

Generally speaking most databases now are created on a RAID with the transaction log being placed on mirrored disks off of the RAID. This gives a high level of fault tolerance and removes the load of the logging from the RAID.

Depending on what your performance requirements are there is generally not a huge difference from what I've seen... especially if you are using Ultra-wide SCSI or something for the I/O channel. You can get better performance on individual disks but you would need more than two to break up the load and carefully place competing hot spots of the database on segments on the different devices. Reading from RAID is fast but writing to RAID is a bit slower than to a single disk.

The biggest advantage RAID gives you is fault tolerance... if one disk goes down the system stays running and the disk can be rebuilt rather than having the database go down and then having to do a recovery from backup. Different RAID products have different levels of 'hot swapability'. With the performace of RAID devices (hardware) these days I see very few databases not using them.

Don

On 12/20/98 7:15:09 PM, Rick DeZeeuw wrote:
> Should one install RAID 5 for SQL Server or just use separate hard drives,
> one for the data and one for the transaction log?