Raid 1

[lozina]

I am looking to configure a system for a friend which should feature 2 hard drives in RAID 1 - due to his extremely good luck in frying disks. Is this an appropriate reason to seek out a RAID 1 system or is it intended for another purpose?

Suppose you have a system with 2 disks in a RAID 1 setup and one disk fails. How does that affect you in the immediate sense? Can you continue working on that machine with the one hard drive? Otherwise what kind of changes would you need to make to use the machine with only the good hard drive while you get a replacement for the failed one?

I am looking at 2x 500Gb Seagate SATA drives, but I need a RAID controller. Can you recommend me a high quality/reliable one?

 

[corkyg]

RAID 1 provides mirroring, which gives you some redundancy. If one drive fails, you can replace it and rebuild the array using the good drive. Or, . . . you can use the good drive on-RAID. Been there, done that. 😛)

 

[DaveSimmons]

His motherboard might already have RAID-1 support, did you check?

Also, that still should not be his only backup. RAID-1 protects again HD failure but not motherboard or PSU problems, operating system glitches, viruses/trojans, human error (oops, deleted "My Documents") and so on.

 

[lozina]

No it would be a completely new system I am building for him.

I am thinking about the following:

ASUS P5QL
Intel Core 2 Duo E8400
4GB Crucial RAM
2x Seagate 500 GB in RAID 1
Supermicro AOC-SAT2-MV8 (RAID Controller)
XFX GeForce 9500 GT
SeaSonic SS-500ET 500W PSU

Does that make sense?

The main purpose is 2D graphics processing - heavy on Photoshop type files. He said he wants to be able to open large PSD files quickly and to make changes and save quickly. He also made it a point that he wants to be able to multitask painlessly - have multiple apps open at same time without much slowdown. Typically Adobe/Office type apps

 

[Zap]

Also, that still should not be his only backup. RAID-1 protects again HD failure but not motherboard or PSU problems, operating system glitches, viruses/trojans, human error (oops, deleted "My Documents") and so on.

+1

RAID is not a backup.

Intel Core 2 Duo E8400
4GB Crucial RAM
2x Seagate 500 GB in RAID 1
Supermicro AOC-SAT2-MV8 (RAID Controller)
XFX GeForce 9500 GT
...
The main purpose is 2D graphics processing - heavy on Photoshop type files. He said he wants to be able to open large PSD files quickly and to make changes and save quickly. He also made it a point that he wants to be able to multitask painlessly - have multiple apps open at same time without much slowdown. Typically Adobe/Office type apps

Go quadcore and at least double the RAM, and use a 64-bit Windows. Get an external HDD for a backup solution (backup = multiple copies). How large are "large PSD files?" If they are tens of megabytes, then maybe a large SSD would suffice. If they are hundreds of megabytes, then maybe some VelociRaptors or fast 7200RPM drives. Use multiple drives so that the application, data files and Photoshop scratch disk are separate. Maybe find out if he will be using filters that can be accelerated by OpenGL/CUDA. If so, then maybe go a notch higher in graphics card such as a GT 240 or 9800 GT.

 

[mfenn]

Suppose you have a system with 2 disks in a RAID 1 setup and one disk fails. How does that affect you in the immediate sense? Can you continue working on that machine with the one hard drive? Otherwise what kind of changes would you need to make to use the machine with only the good hard drive while you get a replacement for the failed one?

Yes, you can continue to use the system. Your raid controller will tell you when a drive has failed and which drive that is either through the driver or at the very least the RAID controller's BIOS. A drive failure in a RAID 1 will cause a slight decrease in performance, but the main thing to be aware of is that you will no longer be protected. When you replace the failed drive (with sata and ahci, this can even be "hot"), you will get a performance decrease while the the array rebuilds because you have to copy the contents of the good drive to the other.

That being said, RAID isn't backup!! The purpose of RAID isn't for disaster recovery, it is to minimize downtime. Your friend would be better served by having a good automated backup solution.

EDIT: I see now that Dave and Zap already mentioned this, but it bears repeating!

 

[Paperdoc]

The RAID1 systems I have encountered do three things if one of the drives develops a fault:
1. Switch immediately to using ONLY the good drive, and do all functions with that drive. There is no significant interruption in performance. This is the core of why RAID1 is so useful in must-run situations.
2. Set a flag in the SMART registers on the hard drive (actually, done by the HDD board itself), and log this into the RAID controller's own messages for review.
3. Send out a message to the OS that should be displayed on the screen in a new window to alert the user that a RAID1 fault has been detected. This will allow an alert user to initiate a proper response. However, some users will miss this message or will dismiss it without understanding it. For that reason, computer support staff should be reviewing all machines periodically to look for the messages in the RAID management system or at POST time during a reboot.

Once the RAID1 error is recognized, most such systems have a way to allow an orderly shut-down of the system, then to assist the tech person to identify the faulty drive, prepare a replacement unit for use, and rebuild the data to a fully functioning RAID1 array. The whole process is supposed to make possible uninterrupted use of the system until an orderly repair and complete restoration can be done at a convenient time. Of course, during that time period the automatic mirroring function is NOT functioning and hence the security elements of RAID1 are absent.

Echo others: RAID1 is NOT a substitute for a backup - that function is still needed. RAID1 only keeps you running until a good repair can be done.

 

[corkyg]

Echo that again. My RAID 1 array is where all my data files live. It provides hardware redundancy, but is not a backup. What I do then is to back up the RAID 1 array to an external HDD on a weekly basis. THAT is a backup, and if necessary, I can rebuild the RAID array from it, and as was mentioned, I can also rebuild the array should one of the array drives go South from the remaining good drive..

 

[heyheybooboo]

Phenom 955 C3 / Gigabyte GA-770TA-UD3 AM3: $228 AR

Saves yah $25 up front with a better proc --- ready to roll down the road with SATA 6Gb/s USB 3.0 ---- uses DDR3





--