Web Hosting Talk : Web Hosting Main Forums : Colocation and Data Centers : Raid 1 or Raid 5?

[attroll]

Now that I have my server and processor all picked out I thought I was all set until someone threw a loop in this one last time for me.

I am going to have a 1U with 4x 250G hard drives. I was going to go with a Raid 1 on the first two drives and have the third one as a backup and the forth as a spare. That was my plan until someone asked why I don't use three on a Raid 1 and the forth as a backup.

It never crossed my mind to go with a Raid 5. From what I read it sounds like a good system because if one drive fails the other two will carry the load and I will not lose any data and it will work fine until until I can send a replacement drive (granted I will need to do it right away).


If I go with Raid 5 will that be faster then a Raid 1 for disk read and write time or will it be slower?

I have no idea which one do go with. I have been on a Raid 1 on my dedicated server for years. So I have not clue as to which would be better. Can anyone offer some insight on this?

[RayWomack]

Raid 5 has the advantage of combining 3 or more disks in your array. Depending on your controller, you can expand your array by simply adding more drives. Raid 1 is limited to only 2 drives.

Raid 5 on some controllers has slower write times, but higher read times. The more drives you put into a Raid array, the better the performance.

The'll be some people to come along and suggest RAID 10. This is the best read/write situation, but you loose the expandability of your array.

[attroll]

I can not go Raid 10 with a 1U and I have already maxed out my budget with what I am getting now, so a raid 10 is out. I am just trying to decide on raid 1 or raid 5.

If I did get a controler for my raid 5 it would be a 3ware 9550SX-4LP 4-port hardware RAID-5/10 controller if that helps any.

[RoryErickson]

If you have 4 disks, you could always go Raid5 + hot spare.

Personally, I'm a fan of Adaptec controllers myself since I've been burn with 3ware adapters not honoring their promised functionality -- online expansion. Possibly specific to the adapters I purchased though. :-)

Some good but really basic information on different raid levels is available here: http://www.acnc.com/04_01_01.html

[bqinternet]

Originally Posted by attroll

I can not go Raid 10 with a 1U

You said you have 4 drives, so then you can use RAID10. If performance is more important than capacity, RAID10 would be an excellent choice.

[idealinfo]

Raid 5 is good stuff, especially if you have a 3Ware controller, if you want write performance you need to use caching, and if there is a potential for power loss you will want a battery backup.

[gbjbaanb]

If you want RAID5, I would definitely put all 4 drives in the array; more drives = more performance.

The best performance for you would be RAID10, where you get the best bits of RAID0 (speed!) and RAID1 (mirrored fault tolerance).

RAID1 with 1 backup and 1 spare is pointless. The spare drive might as well sit in its shrink wrap in a cupboard.

[attroll]

After reading more and listening to everyone I have decided to go with a Raid 10 which will give me the best of both worlds. It will give me the advantages of a Raid 1 and somewhat the speed of Raid 0 and it will give me 500G of storage.