Raid Options

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thekiwi

295 posts

Ultimate Geek
+1 received by user: 7

#18961 31-Jan-2008 10:37

Hi everyone

Just wanting some advise on RAID options for a machine im putting together.

Im wanting to use it for some development work I do in house, plus it will host Exchange/SQL server etc. Was looking at doing Raid1 for the OS and RAID 5 for the Data, but just want to clarify teh hardware aspect of achieving this.

A lot of Cards say they are Dual Channel ... I presume this is what is required to run two RAID arrays on a single machine. But, a lot say that one channel is for internal drives and the other for external ... does this mean if you have a 2RU machine with 6 disks ... you cant say have 2 for the RAID1 and 4 for RAID5, but instead would need an external enclosure for the second channel?

Any advise on how to achieve this would be great. My reasoning, which may be right off the wall, is that the OS benefits speed wise form RAID1, whereas the data components are served better from RAID5.

rhysb

435 posts

Ultimate Geek
+1 received by user: 7

Trusted

#107743 31-Jan-2008 11:41

Most RAID controllers will easily handle more than one array at a time, so having a Raid 1 & Raid 5 array shouldn't be a problem as long as you have enough internal connections for the 5 or more drives required.

A hardware Raid 5 array has very good read performance and should outperform Raid 1 as the reads are distributed over 3 or more drives campared to two in Raid 1. Raid 1 has the advantage of only requiring 2 drives and is easy to implement in software.

If you want even better performance you could look at a Raid 50 array which is basically two striped Raid 5 arrays together. it requires 6 or more drives though.

thekiwi

295 posts

Ultimate Geek
+1 received by user: 7

#107748 31-Jan-2008 11:58

rhysb:
Most RAID controllers will easily handle more than one array at a time, so having?a Raid 1 & Raid 5 array shouldn't be a problem as long as you have enough internal connections for the 5 or more drives required.

A hardware Raid 5?array has very good read performance and should outperform Raid 1 as?the reads are distributed over 3 or more drives campared to?two in Raid 1. Raid 1 has the advantage of only requiring 2 drives and is easy to implement in software.

If you want even better performance you could look at a Raid 50 array which is basically two striped Raid 5 arrays together. it requires 6 or more drives though.

Thanks for the reply.

So if I had 6 drives you would recommend all 6 in Raid 50 instead of 2 arrays of Raid0 and Raid5?
At the moment looking at it all being hardware based.