Best practical RAID setup with Intel ICH9R and Vista x64?

[fpbear]

I'm going to build a custom system with a board that has the Intel ICH9R RAID controller chip but I can't decide on the RAID setup. I know that RAID 0 has the best performance, RAID 1 simple fault tolerance, RAID 5 or 0+1 for a mix in-between etc. but from a more practical point of view, which configuration is most satisfying?

Data backup is very important for my purpose, so initially I thought of buying a couple 500G drives and using RAID 1, which I guess would have a little improved read performance. It is also a plus if this combined volume could be the OS boot drive to keep things simple.

Then I realized, why don't I just go for top speed with RAID 0, and then keep an etra high capacity drive and have some backup software running frequent backups. Then if I lose one of the RAID 0 drives it won't be a disaster since I can recover the files anyway.

With the RAID 0 approach I would need to have a separate drive as the OS boot drive. Unfortunately this also means more messing around with the SATA configuration, boot sequence, and I can't have everything all on the same volume (I like to have Vista and all the data on one drive letter). Also I am not sure what backup software would work best for this (there are so many available, but it would have to be very reliable software).

Should I consider RAID 5 or RAID 0+1 with the ICH9R? It would be a performance compromise and I would still need a lot of drives. Why not just do RAID 0 plus automated backups to another drive? The files wouldn't have to be mirrored up-to-the-second, a few hours out of sync in case of drive failure would be ok.

I know the theoretical aspects of RAID levels pretty well but what would be really useful to find out would be if anyone has experience how cumbersome or convenient these setups are in real-life.

 

[MerlinRML]

First of all, RAID 1 is not a backup. It's realtime replication. That means that if you get a virus, delete your data, get data corruption, or any number of things happen on drive 1 then you get the same problem on drive 2. RAID 1 doesn't mean that you don't have to have backups anymore, it just guarantees that you will have a replicated copy of all your data so that if one drives fails you won't go down.

Second, as to which RAID to use depends on how you use your system and how important your data is. There are really 3 aspects to most RAID levels - management, performance, and redundancy in the event of a failure

RAID 0 is performance's best friend (and data's worst enemy). For every disk that you add, you've just increased performance. A lot of people will argue that it doesn't help with general day-to-day tasks, but it definitely helps with sustained transfers and overall disk throughput and IOPS. Unfortunately, the more disks you add the higher your chance of a failure occurring, which results in data loss due to lack of redundancy. Needs 2 disks but can be done with more (can be done with 1 on some controllers for a sort of pass-through mode, but then what is the point?)

RAID 1 is data's best friend. Every disk gets replicated to a second disk. The problem with RAID 1 is that it is very expensive. You just doubled your cost of disks. It is the best form of realtime data protection, but it offers no performance improvement, and it does nothing for management. If you have lots of disks, you'll have lots of RAID 1 arrays. Needs 2 disks.

RAID 5 is a compromise on cost, performance, and redundancy. You only lose out on a single disk's worth of space due to the parity information. Performance tends to increase with each disk added (but not as much as RAID 0), but so does chance for failure. The higher the chance for failure, the more likely you are to lose more than 1 disk which results in data loss. Performance increase is counterbalanced by the added cost of writing additional parity information, and RAID 5 has the highest hardware requirements for calculating parity. Needs at least 3 disks, can go higher although I wouldn't recommend more than about 7-8 at most due to the increased risk for multiple disk failures.

RAID 0 + backups is a common solution for those looking for the best performance
RAID 1 + backups is good for those needing the best uptime and cannot afford to restore from bacup
RAID 5 + backups is good for those who are trying to get the most space out of their available disks while still having some redundancy in the event of a failure. Depending on the number of disks, you can also pickup a slight write performance increase and a pretty decent read increase, but you'll give up some CPU cycles for parity calculations.

A frequent practice that I use for servers calls for a RAID 1 for the OS and a RAID 5 for data/logs/applications, etc. And don't forget the backups. This gives you guaranteed uptime for the OS, and a RAID 5 array with some increased performance and space for the application side.

Good luck picking what works for you!

 

[fpbear]

Excellent explanation, the best I've seen!

It is interesting - the OS drive is most important to keep running 24x7 on servers, so it is set to RAID 1. Whereas on home PCs the OS drive does not matter as much because Windows can be reloaded in case of failure. On home PCs it is the data such as photos that are worthy of the highest protection.

So I'm thinking of using a fast WD Raptor 150GB drive as the OS drive for fast boot of Windows and programs, and two Samsung Spinpoint T166 500GB drives in a RAID 1 configuration for personal data.

It's kind of "reverse" of how things are set up for servers.

I was also thinking of a RAID 0+1 configuration with 4 300GB drives, but I'm not too sure about the onboard ICH9 Intel Matrix controller for the more complex RAID levels. I am wondering if I will get better performance out of the Raptor as an OS drive, compared with RAID 0+1 on a software based controller. That is the puzzle... ?

 

[Zerd]

The idea of RAID 1 is to have increased uptime. If you lose precious time by having your service down for the time changing harddrive and restore backup, you can save a lot with RAID 1.
I.e. a sale-website. One disk fails, and you're still serving your customers. Without raid you'd be losing customers and money. Still... you can get a virus or accidentally delete your files, and you'll be out of order until backup is restored.

Your setup is quite opposite of that, if I didn't misunderstand. You'd want to save your photos and other files that can't be lost. I don't think RAID 1 will help you with that. If you're not constantly changing your data so that your backups are out of date an hour after last backup, I think It'll be better if you had spare drives that you use for backup. If you need the extra speed, do a RAID 0, and have enough drives to backup that too. In case of file-deletion, you'll have a copy in no time. In case of hdd-failure, you can switch the disks, or insert new ones and copy it back.
Summary: RAID 1 won't help you much unless it's uptime you're after.

 

[fpbear]

Here is an interesting configuration that I'm considering. I just purchased a 150GB WD Raptor and 2x 500GB Samsung T166 drives.

I would use the 150G Raptor as the boot drive for Vista and all program files.

Using the ICH9R Intel Matrix Storage feature I can create both a RAID 0 and a RAID 1 array on separate partitions on the 2x 500GB drives.

Every night, Acronis backup software would copy the contents of the 150G Raptor to the RAID 1 partition on the 500G Samsung. Also, it would copy the contents of the RAID 0 partition onto the RAID 1 partition of the same 500G Samsung.

This way I would have 150G of OS/program space + 233G of RAID 0 personal file space.

If the 150G Raptor dies, I have a backup on the RAID 1 Samsung partition.

If the RAID 0 Samsung partition gets corrupted, I have a backup on the RAID 1 partition of the same drive. According to Intel, the RAID 1 data will still be OK in this case.

This would allow me to experience the WD Raptor, RAID 0, and RAID 1, and take advantage of the motherboard ICH9R, and do it all with just 3 drives to keep cool. This is also a quiet system so I didn't want to end up with the power/cooling needed for 5 drives.

I just thought of this and haven't had a chance to thouroughly consider the pros/cons - am I overlooking anything?