About RAID failure
Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee
About RAID failure
If I build a RAID array and my RAID controller goes kaput is it sufficient that I buy a new controller that can handle the same RIAD level that I have used or do I have to buy the same manufactures controller to get the array back? Or is the whole array gone completely in this case?
This depends on the RAID and controller.
For example, if it was on the motherboard (such as the many fakeraid sata contrtollers, you would likely need the same motherboard.
If it was a discrete hardware card, then it depends on the manufacturer how far away within their product line (or to another mnaufacturer's line) you can go.
The third factor is the type of RAID. If it was a simple mirrored pair then the drives should be identical and changing controller shouldn't be an issue. More complicated types such as 3,5,6,10 etc can be very controller centric depending on how the manufacturer implemented the specs.
If it's mission critical, not only is it wise to keep spare drives handy, but a spare controller card as well.
For example, if it was on the motherboard (such as the many fakeraid sata contrtollers, you would likely need the same motherboard.
If it was a discrete hardware card, then it depends on the manufacturer how far away within their product line (or to another mnaufacturer's line) you can go.
The third factor is the type of RAID. If it was a simple mirrored pair then the drives should be identical and changing controller shouldn't be an issue. More complicated types such as 3,5,6,10 etc can be very controller centric depending on how the manufacturer implemented the specs.
If it's mission critical, not only is it wise to keep spare drives handy, but a spare controller card as well.
Or .... software Raid. Linux software provides reliable, cheap, and slow recovering Raid solution compared to semi-hardware and hardware solutions. You don't need to pay the cost of raid controller card and you get rid of the dependency of the same motherboard(chipset), but you've to sacrifice lots of time when building/recovering raids.
Simple Raid like Raid 0 wouldn't make significant difference; however, complex raid such as raid 5 would cause detrimental difference in terms of performance, time and cost.
Simple Raid like Raid 0 wouldn't make significant difference; however, complex raid such as raid 5 would cause detrimental difference in terms of performance, time and cost.
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Nick Geraedts
- SPCR Reviewer
- Posts: 561
- Joined: Tue May 30, 2006 8:22 pm
- Location: Vancouver, BC
From my experience, if you're working with something like RAID5 or equally "complex", then you'll likely need a RAID controller of the same brand to restore an array. I've moved working arrays from a 3ware 9500S card to a 9650SE without any hiccups. I've moved arrays between countless Intel controllers the same way.
I can say that the 9650SE controllers are top notch. I've got one running in my file server at home and the only complaint that I've got is the lack of flexibility when it comes to email notifications. However, I can overlook this because of the rest of the functionality, performance, and reliability.
I can say that the 9650SE controllers are top notch. I've got one running in my file server at home and the only complaint that I've got is the lack of flexibility when it comes to email notifications. However, I can overlook this because of the rest of the functionality, performance, and reliability.
This should bring you a bit more up to date:
http://www.tomshardware.com/reviews/RAI ... ,1640.html
I'm using a raid 1 which has gone from a cheapo chinese no-brand raid card (lots of issues, lost raid several times, never data) to an Asrock mobo (mobo overheated in my p180, died, no raid loss) to an asus p5ke mobo (also overheating but no raid loss so far).
Physically the same data moved from a 80Gb + 120GB setup (mirrored only 78 gb) to a double 120 Gb (mirrored 114gb) setup to a 120 + 160Gb setup, and now finally to a 160 + 500 GB setup.
It carries all my data of the last 9 years, and even though it will soon be a 500GB raid image I doubt I will ever fill that up.
I'm going to build a raid 5 with 1TB disks for my media files, and run it on the same intel processor. I don't foresee any issues with performance or security from not using a *real* controller, and disaster recuperation will not be an issue as long as I stick with Intel controllers.
conclusion:
If you stick with same brand controllers you'll be able to transfer a RAID painlessly.
Never try any repairing or rebuilding at random, the RAID system is pretty robust if you don't panic.
http://www.tomshardware.com/reviews/RAI ... ,1640.html
I'm using a raid 1 which has gone from a cheapo chinese no-brand raid card (lots of issues, lost raid several times, never data) to an Asrock mobo (mobo overheated in my p180, died, no raid loss) to an asus p5ke mobo (also overheating but no raid loss so far).
Physically the same data moved from a 80Gb + 120GB setup (mirrored only 78 gb) to a double 120 Gb (mirrored 114gb) setup to a 120 + 160Gb setup, and now finally to a 160 + 500 GB setup.
It carries all my data of the last 9 years, and even though it will soon be a 500GB raid image I doubt I will ever fill that up.
I'm going to build a raid 5 with 1TB disks for my media files, and run it on the same intel processor. I don't foresee any issues with performance or security from not using a *real* controller, and disaster recuperation will not be an issue as long as I stick with Intel controllers.
conclusion:
If you stick with same brand controllers you'll be able to transfer a RAID painlessly.
Never try any repairing or rebuilding at random, the RAID system is pretty robust if you don't panic.
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Nick Geraedts
- SPCR Reviewer
- Posts: 561
- Joined: Tue May 30, 2006 8:22 pm
- Location: Vancouver, BC
I'm very happy with the performance of my card. It's sitting in my file server, and as far as I can tell, disk access has never been a bottleneck in any of the things that I do. When transferring files over the network, the gigabit ethernet I run is easily slower than the disk transfer speed.liknat wrote:Thanks for the info and links.
Nick Geraedts:
What is the performance of the 9650SE in real life? I have read posts that it's performance lacks quite alot from the claims of 3ware? How does it work out-of-the-box?
Let's just give you another number to play with. Rebuilding my 8xWD10EACS RAID5 array takes just about 7 hours, while the array is online (i.e. data is still accessible). I doubt that there are many controllers that could match that for performance.
Just make sure that if you do build a larger array, keep two things in mind. First - staggered spinup is a must. Your PSU will thank you in it's old age. And secondly, Western Digital has the TLER (Time-Limited Error Recovery) feature that you can enable on all their drives. Other manufactuers have similar features. If you're running any sort of RAID array on the 3ware card, make sure you have this feature ON. It'll prevent the card from kicking a drive out of the array prematurely (which definitely sucks).
This is a second hearty approval of the 9560SE. I have an 8-port model full of 750GB drives and it easily maxes a gigabit ethernet. It did so back when it had 4 and 5 drives too. Another thing that makes me happy is that the 3ware controller (and other high-end RAID cards) supports OCE - online capacity expansion. This means that I just added more drives to the array and let it rebuild. The whole time it was rebuilding, the old filesystem was available (and not all that slow, either).
I've also had to replace the card once due to no fault of 3ware. Mice. Don't ask. However, I took the drives and put them into the new system with the new card and voila! Everything worked. Migration was seamless (older model to the newer 9650SE).
I've also had to replace the card once due to no fault of 3ware. Mice. Don't ask. However, I took the drives and put them into the new system with the new card and voila! Everything worked. Migration was seamless (older model to the newer 9650SE).