Which RAID Level is Best for Win 2000 Server Logical Drive 1

[JohnBates]

Hi,

I'm configuring the RAID on a new IBM xSeries running 2000 Server.

Will have 2 logical drives under 1 array.

Plan to us RAID 5 for the logical drive that will contain the applications and SQL Server database.

But for the other logical drive - where only the WIndows 2000 Server operating system will reside.... should I use RAID 0 or RAID 5 or ?


any thoughts?
Thanks, John

 

[FredUG]

For the OS I'd use RAID-1 not 0 or 5. Also, database servers like RAID0+1 (mirrored stripes) better than 5 but 5 will certainly work.

Hope that helps,

FredUG

 

[JohnBates]

Thanks Fred,

I may be questioned as to why I used RAID 1 for the OS logical drive. If you can spare a minute to explain the benefits, I will appreciate it. BTW this will be IBM's hardware RAID configuration, not the operating system's. As I understand it, the OS will not see the physical drives after I'm finished. It will just see logicals C and D.

john

 

[FredUG]

Simple, RAID-1 provides fault tolerance where RAID-0 provides none and it only needs 2 drives compared to RAID-5 needing 3+ drives. If uptime is less important than speed then you might want RAID-0.

http://www.robustdigitalsolutions.com/html/raid-levels.html

See above for more details...

FredUG

 

[JohnBates]

Uptime is extremely important - this is a 24 x 6 shipping system. Server will have 4 18.2 GB SCSI hot-swappable disks. Fault tolerance is a must. I just don't understand why RAID 1 for the OS versus RAID 5 since I will have RAID 5 level for everything else.. ?

Thanks, John

 

[ricpinto]

Raid 1 or 0+1 is the fastest performance among the other RAIDs. In case 1 HDD fail, speed will not degrade so we put our OS in this level of RAID. The disadvantage is, it's the most expensive because 50% of the HDD will be offline in case a hdd failure.


We used RAID 5 for data because we wanted to save HDD's and still maintain fault tolerance, although slower.

 

[FredUG]

> I just don't understand why RAID 1 for the OS versus RAID 5 since I will have RAID 5 level for everything else.. ?

You certainly CAN use RAID-5 for the OS if you want to use 3 drives. You'll end up with a larger disk size than with mirroring. I usually just mirror the OS drives but if RAID-5 makes you happier, feel free.

One thing I just noticed is that you say the server is only going to have 4 disks? You cant do RAID-5 *and* RAID-0/1 on only 4 disks. The RAID-5 array will take 3 disks alone and that only leaves you 1. You could do a single RAID-5 with or without a hotspare and then make 2 partitions but that wont change the RAID level.

FredUG