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-   -   RAID question (http://www.hardwarecanucks.com/forum/storage/9691-raid-question.html)

miggs78 August 28, 2008 10:22 AM

RAID question
I had a quick question for you guys. I know RAID 0 is faster (made for performance). Is RAID 1 a lot slower than RAID 0?

I had my lesson of not backing up data, I had a RAID of 4 hard drives, and lost 2 of them, hence data gone too. And I guess in RAID1, if you loose one hard drive, you could replace it without loosing any data.

Tazer-[X] August 28, 2008 12:51 PM

Raid 0 is mirroring
Raid 1 is mirroring and striping
raid 5 is spanned acrtoss 3 or more drives with a drive for parity
raid 5 is the fastest because the more drives you implement, the more drives you have reading and writing at once. Plus you have more cache form the drives.
The downfall is that the best raid 5 implementations require a hardware card, these are about 500 ir so for a decent one that will burst 200 MB/sec and up to or more than 300 operations/sec.
Another option would be to get a raid enclosure and populate with a ton of cheap 60 diollar sata 2 drives. So, if you got a 8 bay enclosure with 160 GB drives, your capacity would be 8 drives X 160 GB - 1 drive.

Squeetard August 28, 2008 12:56 PM

Raid 1 is only mirroring.

Raid 10 is mirror and stripe.

Squeetard August 28, 2008 12:57 PM

With 4 drives raid 10 is your best bet. It runs 2 in raid 0 and mirrors that to the other 2.

Speed and protection against failure.

Jack Rabbit August 28, 2008 01:21 PM

RAID 1 is a lot slower than RAID 0 in common configurations.

miggs78 August 28, 2008 02:15 PM

I haven't bought any hard drives yet, looking at getting 2 of the 640gb ones, I only have 4 x 5 1/4" bays available, I put in my DVD drive and a 3 to 4 hard drive cage in there. I could put in 4 hard drives, I would like to use the on board RAID if possible, but something that would backup data, like mirroring. I don't play very many games or something like that, so I don't mind sacrificing on RAID 0.

Jack Rabbit August 29, 2008 03:33 AM

RAID is not a backup. It only provides some redundancy. If you PS fries it will likely take both drives with it and you lose your data. If your comp is stolen you lose your data. If you accidentally delete a file then it is gone, no "backup". If you are worried about the integrity of your data you are better off getting a NAS or external enclosure and some good backup software.

Every on board RAID controller does RAID 1 these days so you can certainly buy the two 640s and configure them in a mirror. It will look and feel and work just like a single drive but if, for some reason, one drive craps out you will hopefully have everything on the mirror.

miggs78 August 29, 2008 04:54 AM

Well sorry I worded it wrong Jack, that is what I meant, Mirroring, as in it will have data on the other hard drive mirrored (stored).

Just for an example Jack how slow is RAID1 from RAID0, I have used RAID0 before, and I can imagine how fast it can be, how about RAID1

Jack Rabbit August 29, 2008 06:33 AM

Sorry to keep harping on the backup thing. I just hate to see people go away with a false sense of security.

If you take two drives and test them in RAID0 and RAID1 you will usually see RAID0 is 75-85% faster. This is kind of expected. In RAID1 (mirroring) you have to send all the data to both drives. The advantage is there is basically no overhead for the controller/driver because you just tell both drives to do the same thing. In RAID0 you send half the data to each drive so you effectively double the bandwidth. The advantage is speed and the larger capacity but there is more overhead needed to figure out where everything should be written and where it is if you need it so you do not get twice the performance. Older fake RAID chip sets are worse but modern chip sets are getting better and better.

If you search this forum for hard drive posts you can see some concrete examples.

miggs78 August 29, 2008 07:15 AM

Well with your post, I would thankyou for explaining something in a little bit detail, but got me puzzled again. Since you RAID0 is 70%+ faster, makes me think if I want to try RAID1. Maybe I'll just have to ghost my entire RAID drive, and store it somewhere.

Thanks though Jack. :)

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